Melee: Treewarden / holy melee, both of these have up-to-date guides afaik. Any barb build (literally) as long as you set him up right, there is also an iron spiral guide up.
As far as casters go: sorc & necro good as always, mana sorc got a big buff in the patch. Holy caster is pretty underrated altho he is harder to play. One mistake that people who played ultimative and not 2017 make is try to bumrush the game in T1s and garbage gear and suffer as a result. You need to keep your gear up to date now for casters also.
If you wanna try something ranged I'd recommend a bow druid, great aoe, tanky & decent single target.