Just to clarify a few things from my opening post and the discussion going on - good discussion btw
Yes, a larger group size would of course mean re-balancing content, and no, I do not envision that BioWare would re-design old content to suit a larger group size.
Look, I am not complaining or raging about longer queue times in the sense that I feel entitled to have the same wait as say a tank or a healer - I know I have to wait longer as a DPS (sniper), and that's OK with me considering the class that I rolled.
However, the design choice of a 4-man Flashpoint group still baffles me, and that is what I wanted to discuss. By norm I of course meant WoW which has 5 man groups - and just adding that extra DPS slot would probably have a large impact on queue waiting times as DPS in SWTOR.
So, the question is still - why design around a 4-man group with only 2 DPS in the first place? and why not design future group content with an extra or two dps slots? I am sure that future content could be tuned to a larger group size, i.e. less AOE damage going around, higher tank threat output, more boss health etc.
I've read all the "roll a tank/healer" or "DPS players suck" comments, but that is really besides the point. I am not QQ'ing about being a DPS, I am just genuinely interested to know why the design choice for group content in SWTOR is based on a 4-man group with only 2 DPS slots? - and am pretty sure that this design choice contributes to longer wait times for DPS.
A response from a BioWare designer is probably beyond hope here, but I have yet to see that comment here that makes me go "ahhhhh, that's why!".