Drop tunings for my 8 string for sure, and if I'm ever playing music or playing in a band where we use just one tuning, I prefer dropped tunings. I like the chord shapes they open up, and after basically learning 8 string in drop E, I'm really used to the fifth interval between the bottom two strings.
If I'm just playing 8 string stuff on my own, though, I like keeping my 6 string in E standard, so all my ideas can translate over to my 8 string and vice versa. When I get my 7, I'm not sure if I'm gonna keep it in B standard to coincide with my 8 string, or do drop A for awesome extended chords.
For my band Algarothsyum, I play my 7321 in A-standard (ADGCFAD). But I've been writing music for another project in the works that is either E-standard or drop-D (6 string, obviously)
I like alternate tunings because you can come up with some cool ideas you may not normally come up with by accident. For the 7 string it makes no sense to me not to drop the low B to an A. You can play all the standard stuff and have that extra octave lower to go to when you want it. (for most people that just means chugging the open a with a dab of the higher strings once in a while) It's just too much of a pain in ass getting everyone to deviate from standard when jamming with others so I practice standard tunings more than anything. The guitars tuning should never limit you. For a long time I would create a mental barrier and let higher tunings limit me. A real musician can make any tuning work. Took a long time for that to.sink in
My six string guitar is in drop Bb and one my basses have the B string dropped to A and then the whole thing down half a step (drop G#?). my six string bass is in standard though.