So you have a video game that lets you create a superband. You can pick your top 5 vocalists from any era to front your band simply based on voice only, not stage presence or charisma. Also, it would be when they were at their best, not like picking David Lee Roth now vs in the 80s.
Mine would be in order
1) Bruce Dickinson (Iron Maiden)
2) John Bush (Anthrax/Armored Saint)
3) Bon Scott (AC/DC)
4) Stephen Pearcy (Ratt)
5) Chris Cornell (Soundgarden)
I guess this round we will do Rock and Roll as the genre - So you are creating a rock/metal super group