Following @Guvnor’s link back to this thread.
Only have MN to use but love her on offense (use her in defense but don’t know how many times she gave me an unexpected win).
If the question is: “Which reviver hero revives the best” the obvious answer is MN.
If the question changes to: “Which reviver helps you win the most battles” the answer will vary depending on what you want and need from the hero.
MN has highest Rez percentage and can often bring back multiple dead heroes in a single cast. That makes her hugely useful but I do believe it is more effective when you are attacking because you can hold it if there is an advantage in that (opponent is about to fire an AoE that would kill the newly rezzed hero for example).
I won’t speculate on Heimdall and Alby on offense as I don’t have them.
On defense they don’t play the same positions/roles.
MN should never be tank, usually is left wing but have seen her work as left flank on some teams (not common). I only put her into my defense after summoning Sif, without the mana boost and damage mitigation that Sif provides I don’t think MN is great on defense, with it I believe she can be effective.
Alby tends to be another left winger (intentional) that I rarely find changes the complexion of the battle when I face him. His effects are better for any hero that he does manage to resurrect and his mana boost is truly excellent but slow from the wing means the attacking player usually can ghost enough tiles to charge specials and nullify him.
Heimdall makes a solid tank and my view is that he is a special healer with a small bonus chance to resurrect. The overhealing is where I see his secret sauce, making the rest of the team much harder to kill. He can flank well. Makes a TERRIBLE wing, can’t heal a dead hero and low resurrection percentage means he seldom “saves the day” He HAS done so and has made me lose a battle after rezzing all four dead allies but it is RARE that he changes the complexion of the battle from the wing.
Both Heimdall and Alby would also benefit from Sif’s special. Ariel’s too (mana boost).
Ariel - I believe synergizes best with MN of the three.
MN revives with low health, Ariel will cleanse and gives a solid % health boost.
Alby and Heimdall rez heroes with better health so Ariel’s healing is less necessary. Alby and Ariel can really jazz up the team’s mana speed but not sure that adds enough upside. If I had Ariel and Alby, I’d probably just use Ariel on attack and focus on another damage dealer.
IF we expand to heroes that can revive (fighters and heroes that revive themselves such at Atomos and Tyr) then I would vote strongly for Delilah. When she was my go to healer she saved me MANY times by reviving with full mana, healing the team and handing out minions. WONDERFUL.
I do not have Atomos or Tyr. When facing them, Tyr is mildly annoying but can be left until the end.
Atomos in his current/buffed form can now really hurt you so does need to be dealt with. Prior to the buff at slow mana and less damage, he was nothing to worry about, but that is no longer true.