User blog comment:Wario1226/Custom Games "Advanced Options" Idea/@comment-4431813-20130726074406/@comment-5331854-20130729000442

Just noticed it yet, lol...

Never forget that setting team size to higher than the standard of 5 can break the overall design and makes Champions like Karthus and Soraka more viable. Also, more pressure on the servers and overall longer loading time (since the chance of people who needs to load for ages is now higher). A team of 5 is pretty good in itself and would still make Custom TT more awesome when 5v5 is enabled.

Did someone ever tried 4v4 on Dominion, btw? Somehow I imagine that this would be more interesting than 5v5 on Dominion.