Why even have bosses that are always random huge guys? Why can't a boss fight just be an enemy army you have to fight? Battles aren't as easy as Boss Fight in SW. Battle of Geonosis, Battle of Kashyyyk, Battle of Hoth, Battle of Endor, no single end-boss for those battles.
That's why I sometimes like to hope that TOR won't use tanks or heals, just crowd control that temporarily take out half the enemy's side while you kill the others. So far it seems that every class has some form of CC/Mezzing(groin shot, kneecap shot, Sleep Darts, Force Wave, etc.). If every class can CC, then making CC the key thing for running dungeons would mean no one would be forced into a role unless they wanted to. A situation where the only people CCing are those who happen to be better at it than everyone else. It'd be a bit of a focus on skill, but it wouldn't exclude anyone else.
I'm only entertaining the thought of Tanks for the sake of this discussion, and the off-chance that BioWare will fall back on using the Trinity that EVERYONE else uses in their MMOs.
"Sir,we are beginning our search for these rumored 'underwater villages'.They will not stay hidden for long". -Battle Droid Commander OOM-9!