If your playerbase really wants short games and high damage.

Just CREATE a temp game mode, and up damage by 100%, Leave it up for two weeks, ad survey everyone that plays it for more than one game.

Then follow it up with a game mode that reduces damage by 25% gives +10 ad against minions (for last hitting) and reduce towers defense by 25% (otherwise pushing will be a bit too hard). Take another survey.

Boom, easy concepts to create, some real data. Lets make sure the data is actually public too.