I know one of the gripes my friend has about TT, aside from the close pool, easy dragon, no solo ranked, etc. is there's not enough IP gain to be worth playing when you can get ~100 IP from even just losing on an hour SR game. I'm sure lots of people tried out TT once, went "this is kinda cool" then saw that IP and went, "well this sucks, I'll just stick to SR."
An easy fix to stir up some interest in TT would increase IP gains, either over all or scale more per min after 30 min (however they have it set up, I'm not sure on their formula.)
Then more people would play on it giving more of a reason to make those fixes.