Gunnery is based entirely around grav round, which will be doing less damage in 1.2. Grav round will proc every buff/debuff you need (damage reduction, armor penetration, Curtain of Fire procs, HIB damage increase). In 1.2, you'll be more effective using grav round more sparingly, instead focusing on full auto and demo round for PvE damage.
In PvP.. well you'll be even more immobile than now and probably just do less damage unless you like 3 second channels of Full Auto.