There are systems in place to prevent the kind of 'toughing it out' you describe. For instance, if you should die several times in rapid succession, you will find you have to wait longer and longer until you can ressurrect. Die 3 or 4 times in a few minutes and you will be staring down a 3 or 4 minute wait to rez yourself.

Also, the monsters most certainly do heal, any time combat is cancelled with them like, say, when you die, the instantly regain about half their helth, and then a few seconds later the other half. So it's really a one go situation. If you can't take out the mob without dying, you won't be able to take it out with dying.

You can always kill enemy groups one mob at a time, dying a few time. As long as you manage to kill them at a good rate you'll grind the group down and eventually they will be all dead. This is a good strategy for taking down groups guarding a treasure chest for example. But beware, often times the mobs will respawn somewhat more quickly than you are ready for and you'll find yourself being jumped by the group you just killed because you took such a long time to kill all of them.

Overall, there are some pretty decent abuse protection mechanisms in there I think.