5* Rank 4 - expiring T2A ... utility / synergy champ
I have preliminarily put them in order which I am considering rank-up for the three classes I also have overflow resources...
I know the answer is most often "it depends"
so for context...
Elder's Bane / Cavalier complete / Labyrinth initial clear complete
Most important - does the champ offer a unique utility or solution to specific node and or champion
Focus content - 100% Act 6, 100% Labyrinth
Secondarily - questing Champions when main Champions are tied up in AW/AQ
please comment if there are unique uses for the Champion, I rarely use any of these options