So, repeat fight mechanic is good, but dying is not. Though two things:
1) If Polukranos has at least 1 toughness and at least one +1/+1 on him, he could prevent any amount of damage without dying, since the part about removing counters doesn't require you to remove the exact number of counters, you just need one to initiate the replacement effect. Much like Sekki, Seasons' Guide (in Sekki's case, he can prevent damage even without a counter)
2) Polukranos's fight ability isn't tied to his +1/+1 counters. In other words, if you mana to buff him with anthem, aura, equipment, etc, he could continue to use his fight ability, as long as he survives. If you wear a Sword of X & Y or Darksteel Plate you can wipe the board easily, with the former targeting specific colors.