A local band were doing a worthy rendition of Pink Floyd's “Comfortably Numb”. The drummer sat at a borrowed 4-piece, 3-cymbal set. As the tune progressed, it was obvious that fills, comping and interpretation lacked the colour and interest of the originals ... no melodic transitions on the toms, no deep rumble from massive floor toms, the same crash tone on every accent. The drummer did a great job of accommodating, but even one or two more sounds would have helped tremendously.
Look at any prog-rock group on stage and you'll see a major real estate development toward the rear. That’s where the drummer/percussionist sets up. Starting with perhaps two bass drums (though not required), the setup includes lots of rack toms, 2-3 minimum and as many as 5 or more. Floor toms may flank the set, 1 or 2 on each side, and perhaps a secondary snare. And flying overhead, a raft of cymbals. And maybe tymps, bells and gongs behind it all.
I've tried it both ways ... and found out that I don't have the discipline for an 8-piece set. But I also don't feel ‘fulfilled’ on a minimalist set. I prefer a fusion set: two mounted toms and one floor tom. The addition of that single tom adds at least a half-dozen tonal combinations that weren't available before.
Cymbals are another area where more can be better. Some of the old jazzers made do with 2 cymbals. But they always chose cymbals that had flexibility. It was common to say every cymbal was a ride cymbal and every cymbal was a crash cymbal. This to me is a musical choice par excellence. I've heard too many extended sets with a plethora of crash cymbals that sound virtually the same.
I guess what I'm leading up to is that your drum set must match your music and your playing style as well as what it is you're trying to accomplish with your playing. If your music calls for melodic toms, then maybe a fusion kit won't provide enough tonal variety. And if you're in a cover band that does top 40 from the ‘50s & ‘60s, then a 12-piece set is not just overkill, it’s just plain wrong.