It's not just the yelling in the delivery...it's the fact that he has fallen into the cliche "drum mirroring" technique that is prevalent in rap and makes lyrics blend into the instrumental to where the impact of what they're saying doesn't come through.
Of course, those who don't understand the difference between "riding the beat/keeping tempo/rhythm" and "mirroring the drums" probably think he "flows" better now...but I digress.
Eminem's lyrics used to "pop" much more because he didn't tie himself down to the "one syllable on each drum" method. He also knew how to maximize the impact through changing speed and using pauses in the RIGHT places. Now, the only time he uses pauses is when he is splitting sentences between bars...which is eating some of us alive.