I didn't think he was quite saying he "can't" use his pretty voice ... hehe... I don't know why that sentence made me giggle. But I think he was saying that he's often chosen not to use his calmer, sweeter voice in FM recordings because Stevie (and in the past Christine) have the warmer, sweeter side of things pretty well covered with their voices. So he seemed to feel it was best for the group if he did vocals in an edgier style to create more contrast and add a distinctly masculine set of pipes to the mix.
What I took away from the quote was that he is still going to do at least some of the more edgy vocals on the new album, because he said something about how he recognizes it's something he's sort of known for now so he doesn't feel like he should just suddenly stop even if he doesn't exactly feel past anguish so closely anymore. But...I do hope one or two ballad-y type things of Lindsey's make the record. I'd love it if Say Goodbye made it. It's a vocal style for him that we don't hear a lot and I really like it. It seems like it's his folky heart coming through.
I love Christine's Mystified, but I also really enjoy the outtake version with Lindsey on vocals. It is interesting that he didn't do that song back then. He seems to be in a different frame of mind today, so I wonder if he would today?
He has an interesting history with ballads. His ballads are just kind of less orthodox, I think. You could argue Save Me A Place or That's All For Everyone are ballads. Things like Shadow of the West of Satisfied Mind might qualify too. I think I consider Bleed to Love Her a ballad of sorts.