AI already disarms/avoids mines it can detect, so AI shooting player mines wouldn't be much of a problem.
It can disarm but not in combat (unless it cheats, because player can't).
It can avoid mines but it is often beneficial to the player: instead of 1 enemy blowing off the mine leaving his buddies unharmed, whole group will gather around a mine, making them perfect target for a grenade (that will detonate mine).
As for mines lacking, I disagree. Note that the thread hilf linked to is quite old and many downsides of mines/traps have been addressed since. (Cheaper crafting, more trap types, more trapper feats, more supporting items.)
It's nice mines are getting some love, I especially like trapping feats. But it's not like they are cheaper/more damaging than grenades. They are also heavier.
Of course the sequential nature of turn-based combat remains, but that just means you have to plan your trap setup to work in turn-based rather than in real-time.
This is a workaround and also pain in the ass
(needs save&load and lots of predicting movement paths). Nothing else suffers from game being turn based as much as mines. Grenades even benefit from TB - it's easier to hit stationary targets than moving ones.
I'd like to see something that helps to mitigate the problem, like mines with detonators that go boom only when detonator is used or from explosions.