Play what you like I think.
I mean. Leveled up my Sage as healer. And while questing, and doing dailies at 50, I just send in Nadia to round up a group. Then go to town using Force Quake. Rest of the mobs get a rock in their face. That's basically it. Just add a dot here and there. And you have the Sage playstyle. Quite boring to be honest.
Compared to this, the Shadow and Scoundrel are better. Shadow is basically whacking at mobs with your lightsaber with some rockthrowing as backup. Scoundrel has quite a few diffrent options.
My Scoundrel is level 19 and has just finished Coruscant. The storyline so far is awesome with a lot of backstabbing, bravado etc. All you would expect from Smugglers. The Consular story is pretty meh compared to that.
I'm leveling as Sawbones (healer). Might not be the fastest killer. But I find it to be a fun class. Back blasting (with Corso tanking), thermal grenades. Some nice healing to keep Corso running. Next level finally a good hot. I'm happy.
"Sihaya Irulan, Smuggler. Backblasting and dirty kicking her way through Coruscant's scum and villany"