I think many people have come to the consensus that the level 25 talents are effectively a non-choice.
Of the 3 choices: ablative armor, bombardier, and piston power, the obvious choice would be bombardier, and I think it’s mostly due to consistency.
Ablative armor just works all the time. It grants stacks of damage reduction for just existing.
Bombardier seems like an interesting choice, but it’s inherently tied to RNG. I’m not gauranteed to find a bomb through my runs, and the only career that generates it (ranger vet) isn’t allowed to be run with engineer (minus the modded shenanigans). Interestingly, this talent actually has more potential/use on lower difficulties where RNG is more giving for supplies as opposed to cataclysm where it’s a struggle getting bombs (which is the exact opposite of many talents which gets better at higher difficulties because of more density). I propose the change should be an addition of a way to generate bombs. I think it should be similar to the strength pot generation of grailknight, but instead of killing anything, it should be tied to killing elites and/or specials. This would actually help equalize it across all difficulties and make it competitive compared to ablative armor. The number of kills of course needs to be balanced, but I’m confident that it’s a small issue. Personally, I think a larger generation time would be good. I think something like 100 elite/special kills on cataclysm per bomb would actually be balanced since bombs are high impact.
Piston power is not consistent and it procs too easily especially on things that don’t need a bunch of knockback. I propose that the cooldown be lowered a little bit, and there should be a way to manually activate it. Rather than being on hit when the cooldown is up, it should be manually activated through a way such as pressing the special key or crouching before hitting just to be able to choose when to use this talent. The cooldown should then be adjusted to be a little faster somewhere in the realm of 10-12 seconds instead of 15.
With these buffs, ablative armor shouldn’t be the only viable talent, but I’m not sure if it’ll fall behind. A simple adjustment to be 6% per stack to a max of 30% damage reduction should suffice.