I doubt they'll give some of this information, because it'll be too easy for people to abuse that information to manipulate queues. Unless you're at a really high elo, you shouldn't NEED a mic to communicate. The ping system works just fine for most call outs.
There is some sort of problem with the matchmaking this patch. It's been widely talked about, but I haven't seen any official communication on what they're doing about it. I expect in the next big patch we'll get a change to matchmaking that will make it feel better.
As far as the character selection goes, try playing every single character until you feel like you have what you would consider a "good game" on the character. Then the characters you enjoy playing the most should all be purple (I have 2-3 at any time). The characters you enjoy but aren't great at playing are yellow. The characters you are only so-so about are white. Only de-select characters that you would not enjoy playing AT ALL. I only have 2 characters that de-selected (Vindicta and Grey Talon). Don't limit yourself to one character or you might end up in a situation where they aren't available (like when Warden was disabled for a day due to a bug).
