Hello,
Playing a gunner I find them to be in the position that berserkers were in ages ago. Remember when berserkers had to build up MP pre-fight to use their skills using 'sacrifice'? At some point this got patched to berserkers just starting with full mp and removing the sacrifice skill.
Now gunners are basically in the same boat, to get full willpower you have to do the following pre-fight:
bombardment > roll to interrupt it but get the 'one with the gun' buff > replenish > replenish > replenish (and 3 more replenishes after that).
Seems to me that it is a bit silly, it's a repetitive and boring thing to do before a fight. Requires no skill - so why not just simplify it to have gunners regenerate 250 willpower every 5 seconds or so when out of combat? Doesn't change the balance of anything, gunners don't have to do press a bunch of buttons before a fight - parties don't have to wait for the 6th replenish - everyone wins.