I guess my point is what does it really matter if I held them all and any nameless melee with a set of heavy picks killed em or even myself with a dreamspitter or heavy picks. Point is even though the kill count didnt say so those kills belonged to the caster. If a melee stunned his own and killed it then that was contributing but those melees can still do that as frequently as they did before. It's really no different now if you stun a mob and the caster kills it versus before when you stunned it and the caster held it right after other than a few more clicks of your right button.
Pre u9 I would often clear out a quest then invite people in at end for loot. I still do the same. This is a function of the scroll mechanic not the effectiveness of more people in my group. Having more people always helps no matter the class if they are well built and decently geared.
You talk balance but look at the viable characters now in epic that weren't before. Evoker fs, Wis based clerics, Assasins, Spellsingers, Nuking sorcs. Sure pure melees lost some effectiveness but they are still able to join contribute and complete those quests. The builds I mentioned were often shunned in epic quests pre u9.
Even melees have more diversity now as you don't need to be a pick using build with a high stunning blow. Monk splashes gained a lot through high stunning fist dc's. Lower hp on mobs means melee can much more effectively take down a mob without caster help. The only thing really lacking a role now are the ac builds.
I think to say it was more balanced before is an error in thinking. You weren't really needed before except boss fights and really aren't now except boss fights. You just help speed things along. I think it is a little too high scaled to the caster side but only for the exceptionally geared casters. It's now a lot more like the rest of the game where trash is usually handled by casters and bosses are handled by melees.
Granted the dots are a little strong and do infringe on melee roles here more than anything that instakills does.
I think to bring melees back up to par I'd like to see bosses much more deadly. Increase their dmg 50%, give many of them true seeing, lower to hit to make high ac toons effective at tanking, give many of them dispell to strip buffs, give some of them bewildering blow.