I really think that lyrically, Em has done nothing but improved since day 1. Even if you hate his different flows and styles, his different topics, etc. The one thing Em has kept almost 100% consistent throughout his career is lyrical progression.
Honestly, there's no other rapper who can touch Em lyrically. If he's aiming for precision/on-point syllable compound -- making every multi rhyme for every bar of an entire verse, look at half of Relapse/Refill. Punchlines (which for some reason a lot of you hate) look at Recovery, admittedly, some of it is silly but a good portion of his punchlines and wordplay on that album is absolutely superb.
People think Em goes through flows/styles, then gets rid of them. I remember an interview he did late 2009/early 2010 talking about how he's gotten bored for the english language, so he's now trying to see how far he can bend words to make them rhyme (Relapse).
I think he's undoubtedly able to pull any of his old flows/styles/rhyme schemes out of his seemingly bottomless bag, but over the last 12 years or so, he's gotten bored. Hence why he goes through what we see as "phases". Since his comeback it was the accent, it was the regular voice, the slightly tuned up voice, the vocal tearing, the yelling, and now a hybrid between them all (maybe not the accent so much).
Not trying to sound like a Stan here, but as a fan of hiphop as a whole, Em is on a whole other level lyrically. Nobody has his diversity. And don't think for one second that he's not perfectly capable of going back and pulling out those old styles.
