they use the airtime rule in tijuana as well, and according to TKD and AC it works really nicely there.
You guys are acting like this nerfs characters who are in the air a lot. Timeouts DONT HAPPEN THAT FREAKING OFTEN. And they will happen a lot less with a 10 minute timer. Thats what people dont get, you cant time out from the ground. Notice how meta knight never times out from the ground. Snake never times people in general. Falco can time out, but with 10 minutes its gonna be almost impossible unless the other player is really bad.
IT would discourage timeouts timeouts by aerial characters, but pretty much no one has the ability to timeout from the ground. It only nerfs aerial characters like toon link if the TL is going for timeouts, which is not only hard to do on an 8 minute timer, but TL can still camp from the air as long as he isnt intentionally stalling.
Most of the theory craft against it is based on the fact that it nerfs aerial characters, but it doesnt (except jiggs, but who really cares).