Eminem is never going to back music like he did when he was in his 20's. He's a different person, so the music is going to come out different.
I don't think Em is capable of putting it all together on an album anymore though. The production, lyricism, wordplay, passion, overall cohesiveness of the album. Relapse had some solid production, good lyricism, but his passion wasn't there in my opinion. And that damn accent did ruin things, I don't care what anyone says. Had he only used for 3am, Stay Wide Awake, and a few others, it might not have been as annoying, but he used it for damn hear the whole album. Recovery had his aggression and passion back, and the lyricism and wordplay was there, but the production was lacking and he was over aggressive to a fault. Hell the Sequel came close. The production was pretty solid throughout, nothing great but solid, his lyricism and passion was there, it was real good. But even still, songs like Take From Me and Lighters dropped it down.
All I know is if Em still is anything close to what he was even from Late 2009-2011, he's smart enough to know he can't name it MMLP2 unless it's dope as hell. If he releases an Encore or Relapse, or even a Recovery while calling it that, people will call it worse than it is. For instance, a B or B+ album like Recovery or Relapse (IMO) would drop the a C or something to some people.