I think it would make more sense for the upgraded abilities of the hydra and chimera to be bound to Activate Upgrade instead of secondary attack. This would 1) maintain consistency with the dragoon upgrade, 2) separate the hydra's grab from the gas, and 3) they're upgrades so it just makes sense for them to be used with Activate Upgrade. Trivial yes, but worth considering before the first major release.
I also mentioned during the last testing session that I'd prefer energy weapon ammo to be refilled at the reactor with the Buy Ammo bind instead of Use Object, but that's more of a personal preference.
