Hmm, it's an interesting question, but it's unlikely that the turn time will be revised during the tournament! Who knows, maybe this fact will prevent someone from winning, so we'll finish with 8 minutes per turn. Download one hero at a time, and you'll be happy;) And if you download 3-4 heroes, then even 20 minutes per turn won't be enough:)
I agree with Leo, with 2 extra minutes, you can manage to get into another battle that lasts 10 minutes :) or even longer...
I myself haven't always managed to move one hero to the end... but this doesn't happen often... IMHO, there's no problem here...
