I could easily go through your list of questions but seeing I have a lvl 50 Operative and have only been a medic specced Operative since lvl 10 I can only comment on Heal Spec Operative only. While Sorc healers can out heal you (they seem to have unluimited resources) a good Heal Operative willing to learn their class and energy management is a HUGE asset. I constantly am sought after in BOTH PvP AND PvE for healing abilities and since the update to warzones I no longer feel cheated out of hard work (and being first target). I have run Ops and hard modes in PvE and after geting some gear things got way easier. Really I assume just like every class it depends on how you spec, stats you choose to prioritize, and your willingness to work at it. Healing Operatives dont have it easy by far buta good one is an asset.
That's just my 2 cents since everyone is talking DPS. As stated before I have not rolled sniper or DPS Operative so I am not able to adequately comment on them