George Weah and Messi are completely different.
Weah's game was about being explosive over 5-10 yards, something that declines as you get older.
Messi's game isn't about making lung busting runs, he stands still three quarters of the match and then all of a sudden he's done something to change the game.
Weah joined when our midfield couldn't pick a pass or spot a run (as said by Weah at the time), I think the majority of his goals he ground out on his own.
Messi at any club today guarantees you success on and off the pitch, even if we get him for a year the money generated by his presence will probably dwarf any income winning a champions league.