PvE tanks and healers?!

I concur that all classes are capable (with good gear and good skills). But some spec are easier to play good, some harder.
For example currently Scou/Oper healer is hard to play well and doesn't heal as well even when played well, while Sage/Sorc is easy to play heal but very hard to play dps.

Tank is in high demand in master flashpoints. We need more tanks.
For operations, I think tank is often the one to start and find people, if that explains why I think I see more heal than tank need on gen chat (it may also be my bias as an apac healer.). But tank is in high demand too.
Half the team or more is dps so dps is kind of always needed, but also easiest to fill because every class can be dps. It is very hard to find a tank who can't do dps, but I don't expect dps to be able to tank.

All three healers has good synergy with each other, but bad when they team up.
Scou/Oper excels at HoTs, Comm/Merc is king of burst heals, while Sage/Sorc is versatile and can complement either.
Two S/O will find it hard to response to big damage spikes, two S/S results in bubble (pre-heal) conflicts. Two C/M not only see pre-heal conflicts but may also waste big heals on same player; this happens with any combo, but C/M suffer most.

Stealther can help the group get pass encounters, sometimes skipping a whole section, and I'd rank them as having the greatest impact.
Sage/Sorc pull can save a player from an otherwise wipe worthy mistake. I pulled two in my last sm EV's final boss, if I didn't we'd be left with only half the team for the final stage.
Third on my list is probably team-wide buffs, namely raid buffs and shield dome.


I doubt even bioware knows the numbers. Most ops are pre-formed before queuing gf for the gf bonus and conquest points, it's really hard to distinguish gen chat pug from established groups. And I think many runs are a mix of both.

Welcome to the family of food spice!
It should be obvious I play healer a lot so... I'd say it's a team effort, since we can't control how tank and dps do their numbers.
One thing I won't deny is healers has a one way control over wipe. Healer dying is often the hardest to recover from, and my mistakes has led to more than a few wipes.

I personally prefer Balance over Tele; you may find it very very boring - there is no random proc at all and it's less mobile - but it got great survivability because of the massive self heals.
If you are interested I'm writing a sorely needed guide:
http://sheep-y.github.io/swtor/ac4/balance.html

(Madness has a "machine translated" version here.)
http://sheep-y.github.io/swtor/ac4/madness.html

@Dajman

Long story short: You should begin with a class, that is easy to start with and easy to veteran it, so that you can gain experience in the different enviroments - flashpoints, operations, pvp.

Short story a bit longer: 1. Before you enter Master Mode Operations or Harder Veteran Mode Operations (Temple of Sacrifice, Ravagers, Gods, Styrak), you won't encounter any serious DPS checks. You will definitely encounter short burn phases. So, start with a Burst Spec.
2. In PuGs, you will meet many leap-monkey-sentinels or other melee-dps in your group. So, choose a ranged dps-class. As a ranged DPS, you will always have to do the work, while the others are doing raw DPS, so you will learn the mechanics and your class even better - target switch, Knockbacks, Interrupts, CC's.
3. Take a class/spec with an armor debuff. After nearly all classes with armor debuffs received a nerf, classes without one are overrepresented in PuG's. So, you will help your group by providing it.

Your decision should be Gunslinger - Sharpshooter or Commando - Gunnery. Both of them do have good defensives, both classes/specs are viable for all PvE and PvP-content. Gunslingers are probably a bit more difficult. You have to get used to the cover-mechanic. Commandos on the other hand are more mobile. The Gunslinger has some other specs, that can become useful in the future in your career as DPS. The Commando can switch to healing spec if necessary. Mando healing is as easy as sage and there is more healing coming around (at least for PvE-content. For regular Warzones you won't do something wrong with Mando Heal).

I hope, that helps a bit. If you have further questions


@OP: Welcome back (a bit late, I know). Tanks are very much in demand. But, be warned. Assasins/Shadows are a joke atm. They are ludicriously overpowered. Probably there will be some balance changes in the near future.
For raiding, most of the not-so-challenging content became easier over the years. Nightmare (it's called Master Mode now) is still challenging. We are currently a bit overgeared (Ops were designed for 242 item rating - we got 248 gear half a year after released). 6.0 will be interesting, when we won't be overgeared as now and classes hopefully won't be broken with the start, so progressing through the old content will be a bit more challenging.
New content is very rare. We got a new operation over the last year with the last boss will be released in a few weeks, but there is only Veteran Mode (fair enough, it's a bit more challenging then old veteran mode). Master Mode is currently out of sight.