Same prescription with no solution then. Whether he just peaked at 22, was never that good and went years before teams learned to pitch and defense him, whether he has failed to adjust because he is hitting the only way his talent allows or because he is comfortable and doesn't desire to change what worked in the past for him, he belongs in AAA rather than Philly until he successfully adjusts, which I agree may well not be possible.
I think,however, that a natural first tendency is for a player to look back at how he was hitting, when things were going well, and determine what he has changed since then, such as different pre-swing hand position. This often corrects the problem, but Franco's case seems to be more one of the way he was hitting when things were going well won't work now, because teams have gotten better at pitching and defensing him. I could well be wrong, but that's why it seems similar to the Howard problem to me. It's not shedding a new bad habit, it's reinventing yourself to adjust to what the other teams are doing.