everything you say works for a system with automated pairing, automated settings, and a large pool of players
Last one is definitely the hardest part, I agree. The other are more manageable It think.
a system where you click on a "play match" button and then it does it all automatically.
No that's not what I had in mind for the reasons you illustrated pretty well.
I was more thinking at a system where you say at what time you expect to be able to play, and the system automatically tells you the players that might play at these hours (in order of priority those that have the closest elo to you, hence the ELO really don't close any opportunity). You click on the "propose match" option, you set the time, you propose a few maps. When the other agree with the time, he chose the map among those you proposed. When the time to plays comes around, if you're not present, you get malus points.
If we implement some ranking, I prefer to use the rules of chess, which has had a ranking going on for far longer than any videogame
I agree, we haven't discovered any better system yet IMO, but doesn't that have the same problem than with the LOL system? People won't be frustrated?
It would also be good to have an extra dev on the team for this, because coding this will not be trivial.
I'm ready to help on that part this summer, if we agree on the concept