I will work reaaallly hard to be mature here (knowing by saying this I have failed already), because, lets face it, the shoe is finally on the other foot for the git guhd melee crowd.
In short, I agree with almost everything said by godhand-.
The very fact that there was a proven way to negate most if not all summons, and that it was so well-heeled people were almost required to build for it, is the very definition of a balance problem. So too was knockdown, which anyone with sense would recognize was the new "Sap" of feats. Again, the fact that 97% of wizards (nay, even all characters) had to build in 3 lvls of bard + esf discipline all because of one general feat is similarly the very definition of a balance problem.
I won't wax too philosophical here, but this is really just the tip of the iceberg on broken things in NWN in general. I won't go into the history of it, but NWN itself made a lot of sense in vanilla for 20 lvls. You could do increasingly broken things at 30 and the game was downright broken at lvl 40, with entire classes being able to invalidate one another.
Some talk here that a few weeks ago, Arelith had reached some golden age of balance. It had not. Arelith had done amazing things to balance a server for lvl 30 play, but this was really just moving the same chairs around in a room. One thing fixed broke three others. This is evidenced by how we chase our tails going right down the list of classes, where now we are literally at the point where the discussion is on nerfing...bards. Anyone who has played the game for ten years, just think about that for a moment.
A lot of these arguments fail to take into consideration stuff that just happens, despite spreadsheets. Like on your amazing supposedly ultra-dominant new wizard, getting double critted by a weapon master and dying in the first round...because....everything godhand- said, but was mocked for. This happens.
There are a lot of broken things still. Wizards seem to be the new meta, and the new spells seem to help, but building had progressed to the point on Arelith that almost any spell that required a save was nigh unto useless. This wasn't healthy.
I don't know where this all ends. I think a lot of things are still broken (see above, especially the ability to run your saves up). As you can tell, I'm not too upset by splitting the utility of the UMD skill, which was outrageously good in the NWN economy. I mean heck, it takes maxing three skills to reliably open a stupid box in this game, yet for 15 points, you could have u-n-l-i-m-i-t-e-d powah.
So, to sum things up...