This sort of reminds me of the post-Mission Impossible 3 situation where the studio thought about dropping Tom Cruise. In the end, they kept him, and he once again is one of the things that atracts people to that franchise the most. Dropping Will Smith and Tommy Lee Jones sounds like a terrible decision.
SONY has rebooted too quickly lately, and so far, it seems to have done them much more harm than good. Their rebooted Spider-Man series pretty much failed and helped halt the momentum the franchise had with the Sam Raimi trilogy. Now their Ghostbusters reboot is getting a lot of hate. The last MIB film did around 600 million, and while it seems like the reason it didn't make all that much money when compared to the budget, i think that had to do with the terribly planned production. Rebooting another successful film series and drop names like Will SMith and Tommy Lee Jones just sound like asking for more unnecessary trouble.