I would say the opposite actually. Play as a gunslinger for the smuggler as that then leaves you free to play as an operative on the imperial agent storyline which fits much better than sniper. (Played scoundrel first time and sniper but regretted it and since have levelled a gunslinger and operative also). My best advice though would be to just level two imperial agents if you can as their animations are soo much better than the smuggler versions. Theres no problems playing either when levelling as snipers/gunslingers kill everything superfast whereas operatives/scoundrels can either stealth past stuff or use their extra cc/heal utility to stay alive during fights.

I assume you have the base tionese/recruit mk2 gear on? I've not noticed any problems in healing HM fps since they were nerfed. Let the tank pull before you cc (if you need to cc) and keep your trauma probe on him for the ~2 secs it takes to cc. Well as a healer there isnt much you need to do if the group is racing to finish it, just keep the tank and yourself at full health (and watch powertechs/vanguards who might pull agro) and if everyone else is running on and attacking stuff without topping up their health first feel free to let them die without feeling guilty.

The world bosses have a codex You'll never find a pug group for NP the nature of the fight is like doing an ec/tfb hm. Unless you want a wipe I'd advise you to avoid it completely. What they should give the world bosses is a guaranteed 5-10 PLANETARY comm drop straight off the boss (plus what the weekly gives). Changing/increasing the gear drop is always going to be useless as the chance of it being useful to you is likely to be minimal.

This last chest is also not dropping an orange item either.

You know the range of the stun is only 5m right? So once you realise the other team as a stun bubble healer just try more than 5m away when it pops. Every single melee dps class has abilities that hit at least to 10m (whether as part of their main rotation or not) and thus can avoid it. I prefer staying full healer spec on my sage as, like all the other sage/sorcs have said you sacrifice too much healing for a (mostly annoying, but not useful) gain in utility.

So bring down the amount of dr the class has and replace it with more damage... That would fix the entire pvp problem whilst massively helping for pve.