Actually that got changed a few editions ago. The Demolisher Cannon is still in, but you can fire it on the move now. In 7e they did make firing it reduce the accuracy of your other guns though.
Hmmm. That's a shame. Does Wazdakka Gutsmek still get his tripple linked 2 autocannons and battle cannon on his Ork warbike? With a recoil so large that his bike was pushed backwards 1d6 inches with each shot.
I do own over 17k points of Imperial Guard and play it heavily in all of the Dawn of War games that support it but here's the thing: Tabletop is by no ways a mean of justifying a units stats nor is a video game in which each faction is heavily balanced against each other. I've read the lore behind all of them and as a former tanker in the USMC, I know that tanks are very vulnerable even when they have strong armour and heavy hitting armaments. My point is that even if the Leman Russ has almost 120mm of sloped armour on the front of its carriage, a shaped charge of 80mm or larger which is around the standard issue RPG used by Imperial Guard militias toting missile launchers and Orks using Rokkit Launchas would have could easily penetrate it using real life combat data at close to medium range where infantry can counter armored vehicles. Armored combat in which a lascannon, a weapon capable of piercing fortified bunkers and slicing through other vehicles would easily pierce a Leman Russ after at least two shots in the same area or if it hits the turret seam which when compared up against an Astartes crew, could easily be achieved by a Predator MBT or even a crew manned Lascannon team. Your pointing out of crew transportation is irrelevant unless you use the same personnel requirement for each. Astartes take up roughly twice the size of a Guardsman as they wear power armour compared to a regular human wearing form fitting flak armour, which means Rhinos can transport exactly the same amount of personnel as a Chimera. The only reason Chimeras are better than Rhinos is that they have a much lower profile and have armored skirts of reactive plating or in some cases, hardened layers of plasteel and admantium reinforcing as seen fielded by Imperial Arbites who use them. Orks can in their own lore take ANY Imperial Guard and Astartes vehicle as a looted variant. They've captured Baneblades before and even STOLE the one used by Commissar Yarrick before a liberation force took it back. They have in numerous occasions fielded bastardized Leman Russes they had procured from wreckage and even in some cases captured ones in addition to Predator tanks. Even Chaos has done the same with traitor Guard taking or even handing over captured and corrupted Imperial vehicles. The only ones that don't really fit that pattern are Eldar, Necrontyr, and Tau. Also you're seriously going to use the Necron data. Even if you try to balance it with tabletop stats, you cannot hide the fact that in almost real engagement, Imperial forces get their asses handed to them. For example, the battle in The Fall of Damnos pitted Astartes, Mechanicus, and Imperial Guard forces against a slowly reawakening Necrontyr armed host and even though they had a massive 800mm super siege gun, it was one shotted by Necron artillery....a massive gun capable of annihilating entire squadrons of armored vehicles was one shotted. Those so called "uber" Leman Russes were annihilated without a chance by Necrontyr infantry and Skimmers. Those "very weak" Monoliths decimated rank upon rank of Astartes and Imperial Guard armored corps while sustaining very little damage and to top it all off, THEY PHASED OUT AND SELF REPAIRED! Warhammer 40k DOES use reactive ballistic plating though they appear to not have a very good sense of when to use it on vehicles as they only ever seem to appear on Chimeras and Salamanders when they should be on almost every single armored vehicle to increase their life expectancy in the battle field. I mentioned ballistic cages because they're a very simple anti-RPG and shaped charge denial system that any vehicle can take around the turret or basket and something that doesn't have to be in lore to implement...it's simply a logical counter-measure and one people without any armored combat experience would fail to use. If you want to use TT stats all the time, then I guess we're going off the assumption that Feel no Pain is now in the game as well so infantry should just ignore lascannon hits and being hit by Leman Russ 120mm guns or even better yet, lasguns can pierce Astartes power armour in one shot if you get lucky with your RNG or how about that vehicles can't fire if they move too far now...let's make the game turn based as well because table top is the only way to base a game now.
Why are these threads even existing still? Eternal Crusade is meant to be a Third Person Massive Multiplayer Online Shooter in the sense of a WH40k Space Marine + Planetside Hybrid. It is not a Massive Multiplayer Online Role-Playing Game like World Of Warcraft or the countless other clones of it. End of. The idea of Imperial Guard being squads may work in an RTS or RPG game but this is not a game that has been advertised so far to be close to either of those genres. In short no feasible way without making every single invidual guardsman player a Chimera APC.
Which case in point is why the developers even stated that they have no plans at this time to implement the Imperial Guard due to such balance reasons. Why we all may love and want to play the Imperial Guard (Fuck their new name no matter what GW wants to say) they simply can't be done unless we have something more to work off of to make the developers want to implement them. OP vehicles is definitely not the answer.
If a lascannon doesn't melt a LSM or CSP with a single shot then the game is out of wack, it should even take down a terminator.
Welcome to the world of RNG, I've seen players survive 50 caliber sniper rounds to the head because the RNG said the damage was not enough to kill a player at maximum range due to "falloff damage mitigation". If the bullshit can happen, it will. Same logic as to how you can tele-melee lunge several meters in some games at the click of a button.
That Games Workshop's lore-numbers are incapable of translating into RL performance is old news. Bolters, chainswords, and even Astartes power armor would not work as advertised if you tried to construct RL equivalents in line with the numbers given in GW lore. Many Bolter models are physically incapable of feeding rounds from their magazines! What matters is their track record of in-game performance and the roles they are intended to fill in the game. Your twisted view of IG vehicles somehow being the weakest in the setting just because the GW art team couldn't design a military machine to save their life is completely incompatible with any 40k game that has ever been released, or ever will be released. As a result, your entire argument is null and void. Instead of trying to get IG nerfed into the ground because their art doesn't match their stats, you should be arguing with the art team to create models that actually support their in-game performance.
I'm sorry but where does the fact that a 40mm autocannon is considered of being anti-tank capable when using SLAP or HEAT rounds? Because that is a very common weapon armament in both the Orks and the Imperial Guard. Or what about the fact that in the 40k setting almost every vehicle has specialized anti-tank rounds designed specifically to one shot enemy heavy vehicles. The only reason the Leman Russ is even good is that compared to most other factions they have extremely good accuracy on the move, they have the numbers, and they normally utilize tactics that most other commanders would gawk at before using such as the pincer assault formation where they literally come danger close to each other that you could touch the next tank if you stuck your hand out the side hatch. You simply seem to think that the Imperial Guard have god-like tanks when in reality the Imperial Guard BMTs are the equivalent of the Shermans and Panzers combined together (good armour overall and great accuracy on the move) but their major downside is that they still can't survive against dedicated heavy AT which is what each faction can field in large numbers. THAT'S what I am stating. There's nothing wrong with Imperial Guard vehicles, it's that they don't stand a chance in Urban combat when you're running up against around 20-40 players capable of fielding RPGs each and demolition charges if they spend the points to equip them. Similar to how in Blacklight you could mass counter with cheap one use rocket launchers if the enemy fielded a mech and you lacked dedicated AT. If you want to simply balance them only in vehicle verse vehicle combat then yeah they're fine but infantry is the name of the game so far and infantry in this game have so many more ways to kill vehicles than vehicles have to destroy infantry once they get close. You also have to consider that vehicles are going to need a minimum of three players to be extremely effective at countering infantry at close range because one player can't control the main gun, movement, pintles, and sponsons to cover all four angles of approach. Not to mention how you expect them to successfully hold off infantry when another tank comes around that corner. This isn't Fury where a single tank can magically hold off 300 at the same time. You also haven't even stated a single logical realistic example in HOW an Imperial Guard vehicle and their equivalent are considered to be unique and how one side is stronger than the other. Compare a Chimera to an Ork Wagen or Trukk that has say a 80 or 90mm AT gun on its bed and the Chimera has a standard 40mm Autocannon.
Now, I'm not arguing with your post, but I just wanted to point out that this is probably one of those things that is only written that way for the sake of gameplay. In reality orks are not so organized as their codex, they sorta do whatever they want, whereas the more disciplined armies like Tau or The Guard will always have a specific way of doing things. I imagine orks would be more than willing to stick a bigger cannon on their battlewagons if they manage to acquire them. Same goes for their armour. As for playable IG, I hope the devs can figure out a way to properly implement them. I'd love to fire an Earthshaker.