Guage up and tune down if you want to maintain string tension. Guage same and tune down for reduced tension. There is a point of diminished returns, however, when the strings either flop around or don't "drive" the top enough to creat decent tone, or both. In any event the tone and timbre of your guitars voice will change a bit, often for the better, when tuning down. A set-up may be required if you go beyond the guitar's acceptance of string guages, tension, action, etc.

All this stuff eventually compelled me to buy a baritone guitar. My voice (and the voices of many people I accompany) is low enough to make me want more guitar friendly keys/fingering and some other options so being able to tune down, capo up, partial capo, virtual tune...etc etc etc...made it easier to adapt to voices. I often keep one guitar strung with mediums and tuned down a half step simply because that's easier on my voice when I'm at home. Naturally I have to capo up when I'm using that guitar out...maybe I'm one of those folks you mention.

There's nothing wrong with playing around with tunings, and I've found some guitars seem to prefer lower tunings.

Peace, Mooh.