The short answer is no. The long answer is "it depends on who you have and what team you're running"

The real answer is "don't waste your time with arena teams, just farm the solo champ teams and get medals".

Is it just me or are there less solo champ teams lately?

speaking from personal use of fenax he is certainly useful in all arenas if you can keep him alive (same with any other glass cannon champion) and putting fenax against teams of tanks is normally where he shines the most, as for udk i feel this is where he shines even more(hes one of my single biggest counters for udk), as iv had many arena battles where i use a1 on another champion and of course udk takes 1 of those hits for them, but what happens is they both get killed at the same time from a fenax a1 because he hits twice and block revived at the same time, i still use him even now in live arena because most people are clueless to the devestation this guy can bring and what he can do, which works nicely.

Certainly useful for tag offense and live arena (any block revive us good).

Agree with kram on classic, just farm solos and low levels.