But ONLY if they also kept James!!! Why not have two singers, like Helloween. The one who can step in gracefully and sing old songs in his own style, AND the original!
Because in Helloween the two singers are the classic one, and the guy that carried the band for 20 years after the classic guy was fired.
Bringing another singer now would be basically saying "our singer can't cut it anymore so we need a younger one to help out".
True, some bands did hire a backup singer - usually it's Michele Luppi - but it's that, a backup singer, and I believe he plays keyboards in Whitesnake as well, off the top of my head I can't remember any other band that brought along a younger singer 'cause the oldest one has difficulties with performing a whole set.