The problem is team chat. The first thing I do every match is /mute all , because the chance of me getting question ping spammed, flamed, etc. is much higher than someone actually saying something useful in chat. I've been playing this game since Fiddlesticks was released in 2009, and it has always harbored the most vile children you'll come across online. It's like back in 2005 when you'd hear squeakers calling you the n word on Xbox Live, but on steroids.
It's too hard to properly coordinate without voice chat in a real time game such as this one, frankly. That's why text chat has no use outside of flaming and flash timers.