I play a mad bomber gunslinger and what I can tell you is:
Incendiary Grenade has been improved. It now deals more of its damage in the first few seconds and snares affected targets. If the initial hit strikes a target affected by your Shock Charge, that target is stunned for 2 seconds
Is a massive buff, before I would only use it situationaly right after a xs flyby, but now its actually worth using in your rotation.
Hot Pursuit has been redesigned. It is now located in Tier 4 of the skill tree and makes Quick Shot cost no energy for 6 seconds after leaving cover.
This makes refunds so much to my rotation its not even funny, after I drop to cover ss, sc, as I get up and quick draw. There are alot of times where the target still has some kick to him and now instead of being energy staved to do anything I can qs for free. Its like hitting the lottery on gunslinger.