I think that making deletions require admin approval would be just as much a burden as needing admin approval for a quota increase. So if admin bandwidth is the issue here, this won’t help at all.
Serious question - why can’t we simply remove quotas altogether? Or exclude yanked files from counting towards a project’s quota?
Basically, limiting deletions exacerbates the issue some projects have with quotas, so it’s hard to realistically evaluate the impact of limiting deletions if we don’t have a better understanding of why quotas exist, and what problems they cause. From the outside, all I can see is that some projects are limited in what they can upload by quotas, and getting quotas increased is problematic because it either takes too long or the requests get rejected. Limiting deletions removes the only resolution for this problem that those projects can use independently of permission from a 3rd party.