Yeeeeeeeeaaaaah.....
Sorry, truth is truth. In 3.5E around 9th level with experienced players, the number of things that were necessary to track became ridiculous. For me as DM, if you had an encounter with more than one kind of creature, and any humanoids with Feats and spells, then doing anything tactically interesting meant all sorts of conditions and bonuses and debuffs and whatever.
Hell - I had three Vampire template foes that turned out to be more complicated to write up than the party itself.
One player completely re-specced his character when he found out his concept just fell apart around 6th level. Total trap option. He was so disheartened by that he eventually stopped coming. He was new, and the system mastery was too much.
Add to that one dedicated min-maxer that basically built stacks of rules with no personality. He showed us how broken the rules were. (He was also a cheater - with dice rolls, consumable spell component costs, etc. so we kicked him out.)
When we reached about 12th level, on top of that the Tiers were so completely obvious and un-fun that we just stopped playing the game.