Wellers dont really exist anymore. Any class can do it just fine now(always could, just some were cheaper) since its been reworked quite a bit.
In previous versions the well was outside of catacombs and you had to fight a really tough monster. If you died or had to run, that was it, you got nothing. Now when you find a well in catacombs, you can run to town, heal up, and go back to fighting. Also now you can have an entire group fighting that well monster and its generally A LOT easier to kill.