I guess it comes down to "i have to write a lot of things all the time, like all the tags etc so i guess if there is a option to "upload 2nd model stage" that connects both and adds all the tags it would atleast make me post more regular wip uploads (i tend to post a lot of pictures since i'm to lazy to write the tags etc)
so something like a parent system
You upload the first and set it to WIP, that adds a button that can connect it to the wip section in the forum (not create a thread, but where you can put in the link to the thread you did create)
WIP models have a additional tab under edits called "upload next stage/version/sketchvolution or whatever"
- Once you upload something under that tab it connects both of them and adds another 2 tabs (prev and next) (like version 2 links to vers 1 and vers 3)
(that also would add a WIP tag, so it would be simpler to search)
Once you are "done" you can set the last one to "final" so it looses the WIP Tag.
I think that would help both people that upload wips, and people that would view them, to see . ah hey there is a advanced version. Or people that would maybe want to learn something to go and check how it started.
--- also after reading @karolmiklas post, keeping the lights would be a great feature, so not just the tags bit the lights, pbr and the post process (if enabled) so you won't have to think about those to keep a simliar look to the previous version
-------------------- personal wip view
Personally the one thing that stops me is that i have to put in "to much" work for each version, that i just decide to to upload almost done versions at this point.
I never use reupload, i tend to delete stuff and upload it new or just have both there. Mostly to see how many "NEW" people did watch that specific version, rather than having a number where you don't know, is that from version 1 or 2.
--------------------- sketchfab specific
Guess that is the extend you guys can provide for us, the rest comes down to the community in how many people get active in cnc, i tend to post my things on facebook etc due to certain lack of feedback.
The only impact you could to is once you have a nice wip system implemented to create a contest around it, like "5 days" where you have to upload a version each day (with 1 day break to write comments about others (mandatory) ) so overall a 10day "event"