While I have clearly been in the 'Messi is hindering us' camp, I think there are ways to make it work.
If used correctly and with the correct kind of players around him, Messi is still a great player. The problem is, aside from the significant overhaul that is needed, you need a manager who has not only the balls but the mandate to bench Messi.
It needs to be "Messi first sub off" strategy. You need to keep looking for ways to not play him, than the other way around. Saved up for big games, asked to run more for 60 minutes before being subbed off, have a clear plan instead of this 'floating role', not playing Copa games, etc. You do all of this, and I'm more than happy for him to stay with us until he goes to MLS.
However, those of us who think it's best for him to leave are mostly pessimistic about that happening. If it's a similar Messi-centric approach next year, then we're screwed.