Let me start by saying that I don’t think that for example current rotation is bad. On the contrary, I think all 3 assets are good. So treat my below answer as a way to brainstorm getting even better quality content in the sponsored program.
I seriously don’t know. I think it’s more about WHO is doing the selection, not some fixed set of criteria. I don’t know backgrounds of those on the ‘committee’, but IMO those people should be actively developing games in UE, preferably should include some trusted people from community (in rotation, something like peer review in scientific journals). There should be someone there that could evaluate technical quality (including code, documentation, topology, etc.) as well. I think though that the WHO part is good. It’s just that without great submissions there is nothing great to pick from.
The other side of the story is who is willing to submit their content to the sponsored content program. Previous $7.5k was probably too little already for some assets. Now it’s not only $5k max, but also wording changed to “up to”, inflation went up and dollar value is going down (etc.). Even the best committee couldn’t pick great assets if they are simply just not submitted to the program.
Also, IMO changing from ‘free for the month’ to ‘free for the fortnight’ lowers the quality automatically regardless of other factors. There are tons of assets on Fab, way more than on UEM, but quality bar is way lower too. And it’s not only my subjective opinion - actual ‘minimum content requirements’ were significantly lowered (e.g., now you can submit single Niagara particle system, on UEM you had to have at least 10; 1 prop vs 10 previously; environments don’t even have minimal amount of models listed now, it used to have 35 for realistic, 50-150 for low poly, etc.). Add to that various issues with Fab itself (which made a few sellers shift focus to elsewhere). So overall I think there is even less good quality content then before.
Those (and other problems) stack against quality at the moment 