How I see it: You can't drive an LX8 anywhere near full potential with a mouse or keyboard. If that's the criteria for adding it to public versions of LFS, I don't think it passes.
But I don't think that's what the criteria should be. If people are having fun with it, it should be in. The subtle factor IMO is that unless the new tire physics really have made it so much more accessible, the LX8 just won't be anything but a weird machine that only aliens can reliably do anything with. It seems like most people won't get the LX8 beyond what they could get from the LX6 (i.e. they'd end up with the same laptimes walking on eggs around corners with the LX8 and then powering down straights, as they would struggling to properly push the LX6 at 7-8/10ths around corners). The sticking point IMO is that regardless what I or others think, that seems to be below Scavier's standards.