Well Demon Hunter is still good, but if you enjoyed setting sentries and running around that play style is mostly dead.
Wizard is still good for farming t6, and pretty high in GRifts 47 ish right?
Crusaders are near the top this season, with condemn build (melee i know), or stampede which is mid-range.
Barbarians I believe are the fastest t6 clear with raekors, but also have a few other builds that clear T6, just not as fast. (Whirlwind, Leapquake)
Witchdoctors seem to be towards the low end this season as pets still arent durable enough for higher tiered rifts. I see most pet doctors stalling out around 44. However Witchdoctor does seem to have the best support role right now so if you play in group alot that would make witchdoctor's saught after.
Basically, you probably have to choose from DH, Wizard, or WitchDoctor. If you like the new Mauraders set, then go with that. Wizard really hasnt changed, much so again you can decide on that. If you liek to play in Group for high tier rifts then go Witch Doctor (if you like pet based play).