I'm not sure if this has been suggested before, but I would like to propose putting a movement speed increase (at least medium) onto one of the gunner armors. Shadowsun may be the best candidate as it is already weak to certain statuses but only has a lowish bonus compared to the other gunner armors. A movement speed increase would greatly improve the chances of surviving and being useful for gunners especially in the case of the alchemers, which have such slow reload times for their second shot that using it in most situations is impractical.

I know that the ASI will help the reload time in general, but the movement speed would help with other guns as well. Sword armor bonuses focus on ASI and damage because swordies are tanks and need to do a lot of damage quickly in the front lines to avoid being killed themselves, and bomb armor bonuses focus on CTR because bombers need to get their bombs in and get out quickly, so if the point of gunners is to snipe and run and not to do very high amounts of damage then movement speed would probably be the bonus that makes the most sense. Put another way, the hunter or rogue class in other MMOs doesn't do a lot of damage but is very fast and agile.

I'm just posting this as a suggestion and I'm not looking for a debate, so if you're a gunner in support of another kind of buff, I would suggest finding the thread you agree with and +1ing it =)