Ok, I'm definitely going a bit off topic with this one, but here it goes.
I've leveled tank, healer, and DPS, and my DPS character does level faster than my healer or tank. There is less downtime between fights since most trash will get completely destroyed before doing too much damage. I'll admit that in certain instances, healers and tanks perform better provided the player has access to the correct companion, but overall they advance slower than dps.
As for the part about WoW's combat being older than WoW itself, I am well aware of that. However, the fact that the system predates WoW is only proving my point. No, it is not the only system a person can use to build an MMO around and frankly any MMO that clones WoW's game mechanics is doomed to die because most players have grown tired of playing the same game.
I'm glad there are people who are satisfied with their healers and tanks. However, most of the people who played SWTOR have left and never came back. Having seen a ton of MMOs come and go, I've seen all the same complaints aimed at any other MMO that has attempted to clone WoW's gameplay.
Let's look at another set of games for a second: The Diablo franchise. There were countless Diablo clones, yet I cannot for the life of me remember a single one of them besides Hellgate London. Not a single one ever matched Diablo II in popularity and most of them fell into obscurity.
So, as for my tone of voice, yes, I am angry. What is there not to be angry about? The problems that are plaguing this game were easily foreseen and preventable. There are more than a dozen WoW clones (yes, I know WoW wasn't the first to use these mechanics and I don't care) when you combine all the Free-to-play games and pay to play ones over the last decade. It makes me feel like they were wearing earplugs preventing them from hearing years of complaints about games in this genre, and then when their game flops they still don't give any indication that they are listening, thus ensuring a game (that I want to succeed) will fall into the dust bin as other MMOs have.
I understand with what you are saying that it would be refreshing to see different combat mechanics of having the trinity system. But seriously let's face it, the problem you are talking about is not just a Swtor problem, but an MMO problem as a whole and I am glad you do realize that with you statement.
If you like the way Diablo series plays like, then by all means play it. In my opinion, Diablo was largely successful due to brand recognition with its affiliation to the Blizzard name. Overall I think the game is kinda blah and grindy with lacking in story with absent character development. I played D3 for some time and could not get into it. I played 1, 2 and the expansions and it felt to grindy to me.
But going back to the topic. The trinity system has been there predating since Dungeons and Dragons and honestly almost everyone copies from it (mmo and RPGs alike). The idea of the system is that it encourages team work. If you take that away, the frankly it become a solo game, but online. Hell they already give you a companion to start with, so the need of another player to help you in questing is already gone. But to address this what did the developers do? They scaled the game so that even if you have 2 players with companions, its still difficult to do heroics and nearly impossible to do flashpoints.
I like the trinity system, because there's more order involved. Just be glad you don't have to roll a bunch of dice and spend like 30 mins for just 1 combat phase.