It's based on DotA Ded, their main audience is people migrating from WC3 to HoN. So most people will come from there for a massive graphics improvement, new heroes, items and actual ranking, not to mention leaver protection and reconnection capabilities.
As for new people taking to it, once it's actually released matchmaking should rank people of similar skill together, and PSR should do a good enough job for low ranking people to judge similar skilled players. So you won't get raped as much unless you're really terrible, but then you'll just sink in rating untill you get to people your skill level whom you can learn with and eventually bump yourself up again. You just have to have patience for release and then patience whilst you learn the game.