I completely agree with this, and the few other post that mention this, the problem with our survivability is not that we take longer to go down than other class but rather that we can't do dmg while going down.
After playing a vanguard it's apparent that the main thing that makes their dps so high is their ability to get high impact bolt off every 6 seconds basically (lock out time of talent) while commandos/mercs cant do that cause we have a 2 second cast for a 45% chance and a 12 sec cd for a 60% chance to get the proc.
If they really dont want to make power shot an insta cast (it does do about twice the dmg of ion pulse) then a making full auto a 100%(or leave it at 60, not really sure for this one) and power shot a 90% chance to proc HiB could also work as a solution. it conserves the idea of ranged, 2 sec cast (1.5 with talent) is the same as getting two ion pulse off, which pretty much guarantees a proc, (45*2=90). this idea is mainly because it is not impossible to get one power shot off, but when it doesnt proc you basically wasted your time.
ps i know i've mixed in merc and trooper ability names
Or I was thinking if Instant cast is too OP, than combustible gas cylinder allows you to cast power shot while moving.