I kind of know what the OP is talking about. I jumped to a town, and wiped out a fairly large "abandoned" building full of blood mages. It was like, the same 3 baddies over and over and over again. But it didn't bother me. I've noticed several people like to micromanage their people by going into the sub-menu alot, rather than letting tactics handle everything. This can really drag a fight out. I just let my well thought out tactics management do the work for me (I'm an elf-mage, all about party buffs), and rush room to room as some kind of murder-squad. Works pretty well for me (hard mode).
So in my case, three fights then dungeon-over would be awful. But since battles are fast, and bloody for me, a floor full of confrontations would be comparitivly the same. 3 floors of that with little to vary things would be tiring, I will admit.
When I went (back) to the [location], there were 3 or 4 monsters that I'd always fight. I will admit that it'd be nice if there was more variety included in the fights. However, specialized battles as they are do allow you to learn your foe, and adjust accordingly.