If I'm a monk will I see different monster combinations and abilities compared to say a wizard?
No, the enemies and dugeons will generate the same regardless of the class. There is always a sense of randomness in the way Diablo generates, but it is not based on class. This is one of the challeneges of Diablo. If they changed it based on your class the game would basically explode when you were playing co-op.
No. The changes in the monsters occur when:
You are in a party
- Monsters get +75% HP for every additional party member.¹
In a different difficulty level (Normal, Nightmare, Hell, Inferno)
These advanced enemies will have extra randomised abilities, including area of effect attacks, more ranged skills and area denial abilities designed to split up your team. On Hell and Inferno difficulties these creatures will get up to four extra special abilities, turning them into miniature bosses. Killing them will give you a chance to collect some of the best loot in the game.
Item drops improve with each difficulty mode, of course, but once you reach Inferno mode, top level items are divided into increasingly devastating tiers.
This two are the only changes with monsters.