Okay, first off I'm a powergamer, I have little experience role-playing. That is probably why my opinion of the Tactics mod goes something like - "if it ain't broke don't fix it".
Six, you always have well thought out ideas and are obviously blessed with high scores in INT and WIS.
Some of your last suggestions to the mod are ones that have been implemented and I'm playing and enjoying every day. I tend to agree with most of the ones now too. Here's my opinion-
1. Immys belt is a bit disruptive to the rules but as long as she can cast a Summon Monster spell it serves the same purpose - eat up the Dolorious Decay, Hold Person, Confusion or whatever spells. So take it away or keep it, I don't think it matters. The 1 hp thing annoys me but I'm quick on the pause trigger and her potions.
2. Didn't know any stayed open any more, I agree with you.
3. If the armor drops then what would I use my first Limited Wish spell for? Gems - phooey.
4. see below
5. I have no idea what those stand for but I like treasure!
6. I always hated Jaheira's spell selection. And yes, she's been in a cell for some time she has time to memorize new ones.
7. Sure, that means I don't have to waste all day waiting for her to hide.
8. Like you said they would be MUCH toughter, especially on Insane. It's kinda funny how they can go from nonexistant to really tough by adding brains.
9. I just rest before leaving the dungeon and they spawn there and I run out. Now I wouldn't have to do that.
10. I've had several MR's come up for those bastards. Karamozov too, does she have MR?
Back to number 4, that was my main intention for posting. I would love for you to make a mod like that, or any other that you've thought about. With your ideas I think you should spend more time developing your own mods instead of disecting Weimers. And if you really want to fix a broken mod that has potential look at the Improved Battles mod. I would love to re-install that one but it has some major issues.
In short, yeah the dungeon could be improved but IMHO it's fine as is.