If I knew how he could surprise me, it wouldn't be a surprise.
But in terms of making a classic album; I think the absolute key, obvious issue and factor to get right is CONSISTENT production. I think he needs a handful of producers, I'd personally want no more than two or three, and for Em to be heavily involved, perhaps producing all of the initial skeleton melodies himself; no consistent overall sound and patchy music is what let Recovery down.
Relapse had that 'classic' consistency with all tracks bar 'CAB' and "Beautiful", but all the tracks made for Relapse, sound like they were made for the same album, it sounds like one cohesive sound and project, despite the wildly experimental flows and cadences.
So, I definitely feel an 'overall sound' is what needs to be achieved now. If you look at say, The Eminem Show, the reason that feels SO consistent and top-to-bottom spic-and-span is because Em had one particular aim in mind; he wanted to capture 70s rock; infuse that sound in to his rap, and he carried that through, throughout; but the beats are all still different and unique.
But without an overall sound... it will just sound like another bunch of tracks.