What? No, Orcs totally aren't my favorite Warcraft Race, and I have no idea what that Icon is. Looks like a pixely Boy to me.

Lok'Ta-Imean, WAAAAAAAAAAAAAAAAAAAAAAGH!!!!!

The devs could help stop the Space marine being soo overpopulate if its maid clear in the factions info that there not the "good guys" so people who like playing the good guys wont just instantly flock to them

i could see a few playing card games, like magic or space poker

Jobs done!

Unfortunately, I don't think that would do it. Space Marines have been the iconic poster boys for the Imperium and 40k for so long that they've built a massive fan base. That won't go away by pointing out the Imperium is a ruthless, dictatorial nightmare.

Would be nice if it did, though. The Tyranid mechanic evidently isn't going to tie up large numbers of SM players if their mini hives are designed for 4-10 players, so I'm hoping there's a good plan B to stop the Imperial horde controlling whacking great pieces of the world map just for turning up.

From what I understand about the campaign mechanics the more dominant factions will control territory needed by multiple other factions in order to complete campaign objectives. So the more dominant a faction is the more opposition they will face in terms of other factions and tyranids.

That may be so, but if the SM's hit 50% of the total pop it won't matter how many other factions oppose them, they will be able to meet them all with even (or scarily, more) numbers. It isn't that much of a stretch for them to reach it either, since even amongst the 'hardcore' 40k fans on the forums here already, they have a huge preference advantage over the other factions. The (much) larger playerbase that will join the game after launch will probably be even more SM biased because they are the human, 'good' guys and are what they will recognise since the SM's are the poster child of the 40k franchise. The people in this thread are concerned about how they will control the numbers of the overpopulated side, because just hoping that the other factions will gang up on them just doesn't work as a method of control.

Don't forget that Orks will be the FtP race. That will definitely help their numbers.
And then there's Tyranids... I am seeing the SM simply drowning in them wherever they go.

I haven't forgotten about the orks, my guess at the rough % each faction is SM 40%, Orks 40% (35% ftwaagh + 5% b2p), CSM 12%, Eldar 8% unless the devs really really push the CSM and Eldar during character creation. There is gonna be a serious population imbalance unless they hardcode in limits, it's just the sad fact of the matter.

Wow, this Thread is huge [a lot of banter--but it's at least (mostly) fun banter ^_^].

Now onto some constructive criticism (please forgive the verbosity).

Faction population is a game-breaking concern: hordes can swarm any point and take it swiftly/easily (as many PlanetSide players have already mentioned--in this thread and others).
However, this is something that the Developers (BE) wanted the Orks to embrace. To this end; population capping would be an drastic measure that goes against the design plan of an entire faction (i.e. the Orks' WAAAGH).

Increased spawn times for more populous factions could be a quick-fix/band-aid on the issue at hand, but is that fun or functional?
[Yes, I know that--even with the increased spawn times--the popular faction will simply "horde" over any defensible/seizable targets. This has be stated previously in this thread as well.]

While the Increased/Decreased Spawn Times is a potential solution; I feel that the 'Nids could be a bigger threat/control mechanic that could help "rubber band" the more populous factions.

Number of players is one thing, but there is another factor that needs to be considered: Resources.
If Territory = Resource Points (RP) and/or other Bonuses/Buffs; then perhaps the faction owning over a certain percentage of territory should be more susceptible to Tyranid infestations.

And I don't mean in a "Duh. If every territory has a random chance of infestation; of course owning more territory means more infestations." Although, that might still work--it has to be play-tested.
I mean in a "Because you own over XX% of the map; the faction has a +XX% increase in Tyranid infestations than normal."

If having less Resource Points means less Special Abilities (air strikes?), Deep Strikes (drop pods?), and Vehicle Points (Rhinos/Landraiders?). Then less popular factions--unfettered by the increased Tyranid infestations--would have a better chance of defeating the popular factions in a more Resourceful/Tactical way.

This leads our most popular factions making a choice: keep taking territory (under the threat of it all becoming useless), or regain control of their resources (but having less players on the field).

In addition--if having a larger % of the population directly leads to a larger % of territory (most likely)--there would be a larger portion of players potentially willing/wanting to play PvE.
In effect, a significant portion of the larger populations would be "tied up" in dealing with increased PvE instances than fighting the other factions. More players fighting instances means less players fighting on the battlefield. Thus other, less popular factions, can seize the opportunity and strike back for territory.

Now the question remains: is that fun?
The fact that this suggested limitation means "More Gameplay" than "Less Gameplay"; I feel that this is a more attractive solution.
Let me know what you think guys. Apologies if this was brought up elsewhere. If it was; I feel that this would be a potential balancing mechanic worth testing out.

NeedsMoreDakka summed up some already said stuff in a good manner.

I do think though... The easiest way to try and balance it later is heavier marketing for Chaos Space Marines, Eldar and ofc Orks. Try to leave Space Marines kinda in the shadows for a change. Secondly, lower amount of "P2Cool" and other cool customizable content for SM, instead laying more focus on other 3 races first.
Taking all previously said measuares into account too (Increased infestation rate, higher respawn time and so on).

If population balance becomes a critical issue, why not look to Mario Kart for a solution? Give the losing sides better item drops.