As I've noted on #17, 3xx series of legacy drivers are EoL'ed upstream (nvidia).Especially because I highly doubt that nouveau driver is worth it.
So if any GPUs which don't supported by x11-drivers/xf86-video-nv but nouveau (means, too new for x11-drivers/xf86-video-nv but too old for 470 series of legacy drivers), porting nouveau would be wanted once upstream stops providing tarballs of EoL'ed drivers. (When it happenes or not happens is unknown for us.)
And the 3xx series is the last series that supports i386. So users of i386 kernel (not 32bit compat on 64bit base, but actual 32bit x86 base) would want alternatives (not sure how many users still exists).
Another consideration would be porting NOVA driver, but it is developed using Rust and bottom half of it would be require LinuxKPI to incorporate Rust support (should need 6.15 or newer KBI / KPI).
And more, it seems to mandate GSP, so shouldn't work on old GPUs like mine.