I have considered monk but I am not sure what hero I would immediately replace as I think a BIP + ST + Monk is a bit unnecessary? Monk sounds fun but again I am just not really sure what team comps I would run.
Monk is probably one of my favorite classes for regular PvE gameplay and you're still able to do a lot of end game play pretty quickly w/ the Nec & Mes heros, like HM DoA/Deep/FoW/UW. Granted it's not the same as SC time if you're into those, but you can still play through them pretty quickly w/o cons as long as you don't mind micro control.
Though, with my necro's recent disconnected/loss of power death while going for r2 Survivor in pre, I've started messing around with a Dervish.
Been playing with the intent of not dying, similar to hardcore mode in Diablo. Dervish being one of the only classes that I've never really played, I've to say that it's been a lot of fun. It's crazy how much they can solo farm lol. I've also been going through all of the quests during game play, finding new quests to keep for low req & q8 farms.