I really think he just needs confidence. His voice sounds fine, but he half-asses it. When they first started playing The Catalyst, there was similar issues, but now, he sounds fine on The Catalyst because they played it so much that he got confident. The Catalyst is actually one of my favorite parts of their live shows now.
I think Mike sounds awesome on blackout and in between live, and I really enjoyed him on the last part of Valentines day.
Yeah you can tell when he sings live he holds back, whether it's only a little or a lot. But when he raps, he comes out with so much energy. All he needs is the confidence he has when rapping. Also, why did it take so long for No Roads Left to get on an album? I've been listening to a lot lately, and the more I listen to it, the more I question why they didn't release earlier.