In order to want to sign Messi again, Barcelona are willing to lose 11% of broadcasting rights because they will sign a contract involving La Liga and CVC Capital Partners. I don't know if it's the best chance for Messi to wear the Barcelona jersey again, but yes I think he still really wants to do it.
Messi is worth more than any broadcasting rights but the PSG and Messi deal is a done deal they are expecting him to sign today. If you are a barcelona fan I would not get your hopes up about signing messi again.