Don't forget, Preds and Transports have a whole other layer of HP that's not yours. Using it dramatically increases your TTK.

As long as you don't use it as a taxi and leave it undefended somewhere stupid.

Chaos, Eldar, and Orks need to leave them undefended. Then I have to most fun in a skirmish!

Love me Meltagun, named her Betty MeltaLotOStuff.

I don't like vehicles in most games personally, but here I feel like their weapons are underwhelming. That's my reason at least.

The problem I have is when our team needs a tank I pull one and ask in chat for a gunner and nobody is interested, I end up being my own gunner, and said tank dies to infantry. Because tank weapons are kinda mediocre most ppl dont want to get in them, and that leads me to wanting the driver to fire the main gun while driving(it might be wrong in fluff, but from a gameplay point of view you can have 1 driver and 1 sponson gunner(swapping left and right as needed and have a reliable weapons platform, it can be further enhanced by adding a 2nd sponson/pintle gunner)

Well... One way to have the best of both worlds is to have the main gun controlled by the Driver IF there is no one in the second seat. then as more people pile in the driver moves down from control of the main gun to the pintle.

And while the Imp Guard wouldn't worry about stabilizing the weapons on their tanks they are slower to advance, and they have a lot more tanks, Space marines, even the ones not as famous for it, still keep their tanks as mobile as possible, that limits the number of people who have to babysit it because for them man power is usually at a premium

Just do me a favor, don't pull a fully manned Pred (5 guys), in a match with 20 or less people. Just use 3 players instead.

Don't think in TT terms, IG ans Astartes would have stabilised weapons on their tanks because we stop using none stabilised weapons long times ago appart for real artillery. But predator have no such weapon, vindicator has.
Actual light tanks (with approximative same weapons as predator) can move pretty fast and shot an insane number of bullet doing so. Yes W40k in the imperium see a crisis in technology but if they know how to fire train size ammo from battleship bigger than little town going thousands of miles/km by hours doing the same on a light armoured véhicules going up to 60 km/hour (45mikes/hour) should not be that difficult. And speaking about Astartes chaos or loyalist, the finest of all, the Emperor chosen who wear priceless technological armour and the finest weapons the answer is yes they have stabilised weapons on their tanks.
About TT it was a balancing issue that made the tanks move or shot, because on a table two press/Léman Russ/... able to move and shot would lead to a mayhem in the reviving army without any chance to react. Turn by turn is fun but you need to broke things to make it works.

Also the numbers involved actually to fully maned a tank are too big 5 on 100 can pass but 5 on 15 to 30 is a bit too much. Count actually four because the storm bolter is just a joke...

Infantry actually have two hitboxes, one normal and one extra-large for being shot at by autocannons. It's the reason why quad-guns are so vicious (well, one reason)

Don't forget that they're also there so someone can take your well placed Rhino and park it somewhere that its lifespan is measured in seconds so that they don't have to run the time equivalent distance of the Rhino's new lifespan once!

It's a tactical game afterall