I play this game casually, i still dont have the 1st PVP battle since i dont think i will ever get a team max in time to fight someone else before they nerf current top team.
i have notice that on my max chars i have over 1,614 coins that i will never use, even if they expand this mercs is kind of a waste to have so many coins wasted (including coins that came from packs).
why havent blizzard fix mercs when they are max out, there is no need for coins on those caracters, same way as you do with task, once you reach 18 there is no point, give those coins random or something.