In the website clips, Matt Doyle seems to be approaching the songs as a singer, not an actor.
Jenna Leigh Green, for example, seems to have such a clear intention when she is shown singing. She is embodying her character.
Doyle, on the other hand, has the same grimace on the whole time and this is reflected in his voice, which has just a general "sadness" about it. He's not being specific.
(One might say I can't make an accurate appraisal of their performances until I have listened to the entire recording, but you must admit that the clips show the pivotal moments/denouments of several songs.)
Thoughts?
"I am the sound of distant thunder, the color of flame."
CARRIE the Musical