(some of the odd behavior I experienced when testing a high level wizard):
1. On at least one occasion the spell Ethereal Jaunt was "seen through" (as if it hadn't been cast).
2. The spell Energy Immunity does NOT show up in this mod (..if its to "balance the mod", well then that's crap - because a dual-wield character with an absurd amount of elemental damage forged into each weapon does so much damage per round that it can kill just about anything in a *single* round - especially if it has attacks of opportunity.)
3. The spell Silence (2nd level cleric/bard) seemingly avoids any spell resistance, saving throw, or spell level immunity calculation. It also seems to penetrate Ethereal Jaunt. Furthermore it seems to extend *well* past the time limit (even if its extended). WTF? The ONLY work-around then is silent spell or auto silent spell (to what ever level). I have NOT tested to see if any of *my* test characters have this absurd capability.
4. I've failed savings throws when the calculation could NOT have failed (i.e. no rolling a "one" and having a LOT more points than the opponent). I've noticed this flaw in MOTB as well. Pisses me off something fierce.
......
*EACH* of the above were unbelievably annoying but..
#1 - was very infrequent.
#2 - I could partially work around it (I think), using other spells and the ring of elemental resistance.
#4 - It didn't appear that Spell Resistance calculations (in general) were fubar'ed, so I still had a variety of options/spells (despite never being able to surpass an opponent's save).
BUT,
I just couldn't get around #3 in a satisfactory manner.
That was pretty much it - GAME OVER.
..........
The simple fact is that an Epic Level Wizard (properly equipped with equipment and spells) should be able to take-out ANYTHING.
I was working on just such a build, but there seemed to be SO many things wrong within "Battle of the Builds" that it just isn't a good environment for testing magical characters.
........
Oh, and I'll add on other thing:
There isn't a spell in-game to lower AC, and that's profoundly screwed up - it directly effects your ability to disable an opponent (or hit it with a touch or ranged attack). The reason it's truly fubar'ed?
Virtually all good epic levels builds will make a save and/or have freedom of movement and immunity from mind effects. (Most disabling spells are mind effect spells, the ones that aren't are usually based on a fortitude save.) This removes ALL spells BUT the Bigby's Hands spells with a grapple component. Unfortunately though the grapple component checks against the opponent's AC level, and fairly high AC levels will defeat the spell's grapple.