He’s been discredited at the Yard and EVERYWHERE else. Lestrade would want him to solve cases again (after thoroughly punching him), but of course the higher-ups wouldn’t want that at all and will keep a very close eye on Lestrade if it gets known that Sherlock isn’t dead after all.
There will be a HUGE media circus, much more so than before. Sure, the public memory is short at best, but the press would just dig it all up again, you can’t keep that from happening if THE Sherlock Holmes reappears. If he returns victorious, having taken down all of Moriarty’s henchmen or whatever, I still doubt that they would see him favourably or even believe him (after all it was all done undercover -going by the book canon- and everyone had thought for years that Sherlock hired Moriarty as an actor), and you can’t just turn the public opinion like that again.
I’m sure Mycroft will be able to pull some strings, but honestly… I don’t even know.
So what. WHAT. Will they just keep pretending he’s dead and make it an underground thing (oh my god I would LOVE that, but of course that’s not how it’s going to play out), or are they going to pretend that there aren’t going to be ramifications that big, or…?