I thought he was o.k. in "How To Succeed". I saw his YouTube videos only. He seemed to have a certain appeal and charm. He has been quoted as saying that his voice doesn't really translate all that well to Broadway...or something to that effect. At best, Criss has a slender voice (like a young Matthew Broderick, perhaps). His vocals, I think, will be stretched to the limit in Hedwig. Who knows? He may well surprise people who are skeptical of his casting.
"Noel [Coward] and I were in Paris once. Adjoining rooms, of course. One night, I felt mischievous, so I knocked on Noel's door, and he asked, 'Who is it?' I lowered my voice and said 'Hotel detective. Have you got a gentleman in your room?' He answered, 'Just a minute, I'll ask him.'" (Beatrice Lillie)