The thing I find the worst is how some mobs cannot be interrupted at all, making them virtually impossible to defeat solo, duo, or even with a group (only applies to lowbies). For example, the Hole. With the new AI/mob types, undead are immune to stun, stun type mezzes, and crits. In the Hole, there are both undead paladins and enchanters. Enchanters can then mez us without any chance of us interrupting them, via spells, bash, or melee. They always succeed. paladins, with their massive manapool (for a 30 paladin, they can sure heal a lot, and stun), are so hard to kill. Granted, it's a dungeon, but bash/melee should interrupt any casting. It's not a matter of stunning them, as undead are immune to, but interrupting their incantation. I don't care how focused undead are, if you knock their hand when they are casting a spell, it's not going to go right.
Also, a suggestion. Make a silence type spell or a non-stun spell interrupt spell. the interrupt style doesn't work on these mobs (it's stun based and also not very frequent to interrupt a mez or heal by these mobs). Make like 15 seconds or so. This way, we can stop mobs from casting long enough to defeat them. (of course, this silence spell would be hard to balance, especially on which class(es) should have it.)
Manataps also are rather ineffective against these mobs. They have too much mana to sieve out, and in the hole no class gets a spell/song that destroys mana anyway. Even the 60 bard song, which does -220/tick for 3 ticks is hardly enough. Mobs regen mana quite fast.
Another suggestion I just had (damn this post is long) is to give wizards a spell that does damage to both mana and HP of a mob. (like destroy 25% of the mob's mana and do that much dmg to the mob. Ex: Mob has 4000 mana. Wiz destroys 1000 mana and does 1000 dmg to the mob, or make it a fixed amount)
Of course, I want everyone to know that I WANT this new AI. i want mobs to form groups and rogues to try to backstab us and mobs to patrol out in dungeons when players stay in the same spot for too long and mobs to run back for help sometimes (like in harder dungeons, I know there are already unsplittable mobs)
Okay, I'm done now. Let me know what you all think of this, or better yet, Wiz just implement it because it's such a fabulous idea of mine!