Which champ to focus on

Kf4st87

I was a bit lucky with Premium crystals to roll up some 4* champs and no I have to all the time thinking about which champ to focus on. Please provide some recommendation for AQ/AW champ which I should focus on or if is better to wait for another champs.
Actual progress is ACT1-3 100% and almost all Event quests 100% so I try to focus on ACT4 exploration, AW, AQ and Arenas to maximize the possible rewards.

Stellan

Warlock! Great for nearly everything.

Svensktiger

Y warlock and then Colossus.

Dominic518

In my opinion you should improve first X-23, WARLOCK, DOCTOR VOODOO, COLOSSUS.

Thicco_Mode

Voodoo