While I love Recovery and it certainly is the album of the year for me at the moment (we'll see when The Roots come out), I understand what you are saying with his flow getting tiring.
I think part of the magic of Em was his ability to tell a story or to speak his mind and the words just happened to rhyme. Sing For The Moment is a classic example of this. Now his flow seems awfully choppy as many of mentioned.
But really, I think the biggest issue I have is his insistence on yelling. His vocal volume is what can get really tiring after a while. Songs such as "Soldier" are so angry, his words are dripping in venom, yet at the same time it isn't necessary for him to yell the words. Songs like "Love You More" characterize his anger, along with his chorus that is actually sung instead of the constant layering of his voice that reminds me of hip hops' autotune persistence.
Don't get me wrong, this album is GREAT, and the yelling at times works REALLY well. His layering in Drop the World was one of the coolest things I've ever heard. However it seems to be that his new style gets a little tiring.