Guess then i am one of those players with niche taste. The atmosphere was awesome. Lady Vashj is one of my all time favorite fights. And our guild didn't have any issues building 2 raid grps for Karazhan at the beginning, but you are right it was a bit annoying but manageable.
But this doesnt mean that the raids nowadays are worse, they are also designed very good!
Somehow raiding felt more epic in the old days with only one size to me.
Even though my guild didn't clear every raid in TBC for example, it was ok for me and my guild and motivated us to try harder next time.