I know this has been mentioned... but just for the people in the cheap seats, I'll say it again, cause they might not have heard. Disables kill meditate.

That means stun, no more meditate.
Silence, no more meditate.
Taunt, no more meditate.
I'm almost positive that forced movement also kills his meditate (like Draven's Stand aside, or Skarner's drag).
Fear is the only one I'm really really not positive about, but I believe that kills his meditate as well.
With so many counters to that single ability, it's not that big of a deal.

If you see Yi start to meditate, someone hit him with a stun or a silence or any of the other things that disrupt him, and finish killing him. Of course, this means getting caught with him 1v1 can be a problem if you yourself don't have a disrupt, but for team fights, it shouldn't even be a factor, unless no one on your team has a disrupt, in which case the problem isn't "Yi OP!" it's "Our team sucks!"

Thank you, and goodnight.