OK, I guess this deserves some commentary.
My first impression is that these changes appeared a few versions ago ... but I'm just hearing comments now. Were most other people bothered but silent? Or did most other people just not notice?
My personal impression (yes, I do playtest these things before foisting them on the unsuspecting Sola world) was that they made things slightly more difficult, but not really. Greater Mummies are 14 hit dice creatures -- that's decided more than an 8 hit dice Illithid. But GM's are notoriously weak (XP on the hoof, as someone once said, expect for the weapon enchantment requirement). This was supposed to make them a little more dangeous. If all else fails, run away. It's not like they move all that fast. :-)
All of the "normal" non-Lich undead are still easily slain by pro-undead scrolls.
Now, as for the Liches: the "improved mages" code (many, many moons ago) tried to do something similar by having liches notice if you were attacking them from a pro-undead shield. They would cast remove magic on themselves in such a situation, hoping to get you. The problem was that the range of RM is too small, and you could be sitting at the end of the screen throwing axes at them or something. Hence the Uber Teleport Field. By an interesting quirk of Infinity Engine stupidity, it is entirely possible that nothing you put on your characters will block this spell, since it technically targets the mage. Certainly SI:* is unlikely to work. The Ritual Boots will still prevent your buffs from being dispelled, as will being a higher-level caster than the lich (which is, admittedly, unlikely).
Anyway, they should only do that move if they are already paranoid and there are no enemies present at all. If you never attack the lich or cast a spell at it, you should be able to run away (let me know if that doesn't happen). In addition, you should be able to sacrifice summoned cratures -- no "come back my pretties" while anything green is visible to the lich.
Now, I'm curious as to what others think. Has everyone been silently rubbing bruises from an undead smackdown? Or has this not really been a big deal?