Personally I run 3 Energy instead of 3 Paralysis. Really depends on what you're looking for. Blind is probably better than Paralysis in a PVE context though. If you're mostly interested in damage, run an Ascension or Health set with a Paladin set. 3 blue / 3 green seems to be accepted as the best damage-focused loadout, but 6 greens is still superior for the heal.
I don't know whether the Sentinel or Gunner is better. Sentinel's a 4* and Gunner's a 3*, which seems to point as the Sentinel being better but IDK. Sentinel is better at defensive support, while the Gunner is more offense-focused (especially in a damage over time team). Judging from their stats, it's hard to say, especially because Bomb scales off 3 different stats. Sentinel has about 1000 extra HP, and about 40 extra DEF, but the Gunner's MAGIC is higher by about 25 points. Once I bring my Gunner Bomber to lv100 I could check.
Sentinel Bomber probably has better 1st turn damage due to his Passive's DEF buff, but Gunner at least neutral damage to all classes