The whole enrage timer stuff is a DIRECT result of the small group size, there is no way to argue it.
It is related to the whole solo path to cap VS grouping and risk/v/reward and all that but the core problem is the same.
If you have 4 people making up a group, the ultimate end of making content 'hard' for those is more strict than if you were designing content for 6 people to be hard for 6 (or extrapolating to raids, 12 instead of 24). Dang, didn't eq1, the mother of all MMORPG's have 48 person raids? (not that I"m advocating that )
In a larger group size mechanic, there is more flexibility, 2 of the 6 could be less than optimal IF 2 of the other 6 were above expected and the group can still clear a zone, and the zone still be 'hard' (ie if 2 of the other 4 weren't above average they would still fail)
I'm a current eq2 raider and I really don't like the super small group sizes in swtor, but if they are going to go that route, it would seem to me that there are better mechanics, like a dps floor on a particular name in a group, or something than the current hamfisted timer fail.
I've always been a fan of making 'hard' mode fights 'hard' due to coordination primarily, rather than gear or group makeup. Though again, with 4 people in a group, its harder to make coordination a factor when the requirement of each 'role' is so set in stone by the lean makeup.
You can rip off any mechanic from other games to make stuff hard, more aoe that needs to be jousted, death prevents, dps floors, dps ceilings, waves of adds, clicky items, adds to be mezzed, order of mobs, cures of effects, interrupts, positioning, special item progression debuffs, off tanking (kinda' useless with 4grp setup), straight gear checks, etc...
I know swtor does a bunch of these already, what I don't get is why some combo of the above can't be used to make a 'hard' mob 'hard' instead of some arbitrary enrage insta-kill timer BS.
It just seems lazy.