I'm fine with overlapping, if you have adequate space to fit everything. I wouldn't want to bend down and twist knobs between songs, so if that meant having 2 delays, one set for a slapback and one for a long delay, that's fine. In his setup it's a little silly because he has the ability for a ton of presets.
I have a bunch of redundancy on my board on purpose for that reason, and for total coverage and flexibility.
4 dirt pedals (plus the Carvin Vai Legacy tube powered VLD-1 off to the side)
2 analog chorus pedals. Each set for a specific sound (plus the brilliant chorus built into the Roland JC)
2 full analog delays. Different rates etc.
2 digital delays (one of which has 4 delay types including digital, analog, analog with mod...)
2 reverb pedals. The Holy Grail because it's a fuckin' Holy Grail!, and the TC HOF 2 because SHIMMER, BITCHEZ! (Plus the GIANT new reverb tank in my JC)
2 compressors. 1 for full tilt max compression, 1 for much more subtle use.
The rest of what's there doesn't need any redundancy. Wah, gate, flanger, phaser, pitch shifter.