my guess w/ no evidence would be
~85% of ppl play qm regularly
~40% of ppl play hl (i feel like this is a highish guess but I dunno)
~20% of ppl play unranked
~10% of ppl play tl
~3% of ppl play ai
I can't find it off hand but they gave stats on this. It's more or less what you said excepting AI, I believe. I think there's quite a bit more AI play than people thought, but in general Unranked and TL are significantly lower pools.
i dont expect new players to see long queue times, but that is also like the realm of uncertainty where they try to identify smurfs and in general don't trust your rating, I'd imagine there are more calculations and rules involved with newer accounts
It didn't used to be long queue times. It may not be now, I'm not sure. They were definitely longer for a bit there, though, because Blizzard came out and addressed it and said it was due to some issue in the algorithm IIRC. Last time I saw it pop up in thread I remember someone in here who was new complaining about times in the not too distant past...though that could've been complaints about 2 or 3 min queues for all I know.