About ranked play during the Blizzcon Q&A from the Reddit live thread:
"They don't have anything specific at this point to talk about, but have been doing preliminary design. They've been talking with members of other game teams (HOTS, SC, etc) to get a sense of what works well and what hasn't worked in the past for Overwatch. They're hoping to have something for launch in terms of ranked play, but if they don't have something they're happy with by then it'll be a post-launch feature."
The ranked mode in hots has actually evolved an insane amount to the point that many moba players now consider it one of the best mm systems aside from the fact that it can have bad mmr matchups due to low player count. If they do something similar allowing for a solo/duo queue mode separate from the 6 stack mode I really think the ingame mm could be great.
Aside from Hearthstone blizz actually has pretty good ranked systems imo and if the OW team has been talking to their other teams I expect a great mm system.
I haven't played HotS, but this might have implications for OW: http://www.pcgamer.com/heroes-of-the-storm-is-getting-a-new-matchmaking-system/ seems like they will trade off que time for more balanced games.
from my experience with blizzard games, I don't get very even matches. I'm a level 18 in HOTS and last game I played had 2 rank 1s on the other team through some weird MM magic, which is a pretty common occurrence for me to be 400-500 MMR below everyone else in the game. Also had issues with HS, but that game is entirely built around getting destroyed by legendaries until you pay up and buy packs and expansions. hopefully HOTS reworks their system and I can believe again
Discord