The best out of three rounds were basically chosen to prevent hax from taking an annoying toll on the matches but i see where you are coming from. However, by the end of this we will have 20 Elites so i think it shouldn't be that bad, if it does get out of control I will take your advice though.
About the Dark Horse benchmark i actually like 40 because it lets you use some Pokemon that need more love like Keldeo and Landy, besides after those few you get to the Dark dark horses. But concern noted I will get some more feedback and i may change it. If not 40, 60 looks like a decent benchmark