okay I'll bite, it's not the first time this is happening, but WHY?
I think if you were to inspect most VNs with walkthrough types of mods, you'll find only one per VN linked on the OP - at least among those currently in development or finished within the last couple of years. I'd also suspect that when the change was made to link only one of each type (walkthrough or all-in-one, music, gallery, etc.) the link that stayed was the first mod attached to the VN - so if someone else did the first mod, they get the OP and if Sancho did the first mod, he gets the OP.
The things I look for in a WT style mod are: pathing notes (style of path, whether a decision gains points, closes off a potential LI path, etc.); hints or notifications for hidden object triggers or collectibles/achievements; ability to change dialogue box easily; gallery unlocker to use if I get to the end of multiple runs and still haven't unlocked a particular scene.
Stat screens are nice, but not essential to me, and the ability to cheat stats is something I have almost never used. I know how to change things like fonts and sizing in the scripts or gui files, so while those are nice, they aren't essential to me and I've rarely used them in any event. If the version on the OP gives me the things I want, I'll usually grab it; if it doesn't, I'll look for Sancho (and then I'll bitch about having to remember to use the Shift key if I want to take screenshots


).
I may be mistaken about why Sancho won't appear in all the places he once maybe did (maybe he did piss off the wrong person

), but other changes to clean up the OP (no links for compressed, for example) seem to have been taken to reduce the amount of maintenance and the workload on those that have to update the OP links. With thousands of VNs, I imagine that can get fairly cumbersome for the staff, admins and mods here.
And, as you noted while I was writing this, it's easy enough to link to the Modder pages for your favorite versions of mods for different VNs.