They do need some adjusting. Without their hardeners they're far too weak. With them they're practically invincible (-60.86% incoming damage)

They go from ~5k ehp & ~150ish reps to ~11.5k ehp (presuming the plate, dual hardener & single rep) with roughly ~400 effective reps once both hardeners get activated. Their reps outpace incoming DPS unless you can find some *massive* burst or have way, way too many people shooting at target. Their effective reps get even wilder if they drop the plate for a second rep.

Or something like that, I'm tired and not mathing well.

The problem is largely that this is all done in effective hitpoints, which means that the damage reduction is *insane*. If tanks were to have higher raw hitpoints, and lower hardened values alongside lower proportional reps... people wouldn't be as upset, as tanks would take damage that actually sticks for a bit.

The large other portion of the problem is that vehicles have isk costs that treat them like they're temporary powerups (and yes, isk IS used as a balancing feature in this game, like it or not) so when someone calls out a 1m isk tank they feel like it should 'buy' them a lot of power, because risk vs reward. Another issue is that vehicles take up an absolutely massive amount of SP to be any real good which really messes with their design, as it treats them more as a role than a temporary powerup anyone could purchase... so there's a second hurdle there. Thirdly vehicles lack a very well defined role other than 'roam around and kill whatever you encounter' which further adds to frustrations - If they had a clearly defined role, people would be less likely to pull them out in situations where they're not needed.

If isk costs remain so absurdly high, SP costs should go down, and survivability should probably be retained.
If sp costs remain so absurdly high, isk costs should go down and survivability should be lowered (no one likes dying, but I care less about dying in something that costs 20k than something that costs 2mil).

Vehicles need clear and frequently useful roles, without people getting upset when they perform well in the roles they have (currently people get really upset that some tanks are good at slaying... because well, that's the only identifiable role they have, and then vehicles get nerfed into uselessness... which causes a set of buffs later down the line that breaks everything because they still don't have a role).