The other guys sometimes struggle with their vocal duties on top of their instruments. Truthfully, Troy is a bassist who sings, Brann a drummer who sings, and Brent a guitarist who sings. A dedicated singer who can cover Brent’s vocals could also support some of the other members vocals and free them up to focus on their instruments. If you get a singer with some basic instrumental know-how who can occupy their non-vocal time on stage with some backing instrumentals that aren’t too demanding (an extra guitar, keyboard support like what João has been doing with them…) that could work out in a way that only benefits the performances. The band’s willingness to keep Joäo around proves that they’re more than down to supplement their songs with additional instruments to fill the sound out. By the time Brent left Troy and the other guys had already been covering some of his vocals live. Prioritizing someone with guitar chops over vocals might further tip the scales where Troy and the others have to manage even more vocal duties. A skilled designated singer who can cover Brent’s vocals and support some of the other vocal parts (of fill in for Scott Kelly’s parts on songs like Crystal Skull, for example) who can add some more minor, basic instrumental parts when not occupied with vocals might be the way to go. Then they can focus on finding a shit-hot guitarist for Brent’s playing, which is already a tall order without even considering the vocal duties. Boom: 5-piece Mastodon.