It seems like some of you are not understanding just how much of a problem something like this could be for the site.
Let's keep in mind that this proposal was made for the benefit of regular users. That is, those that are subject to upload limits and the modqueue. The only way it would be possible to give them the benefits they want is to allow them to upload deleted posts without using any of their slots. As a result, every member can now become an Anti-Contributor. In other words, a user with uploading privileges equal to a Contributor, but only for posts they choose to delete.
I already explained that a troll could upload a bunch of shitposts. This is in fact very likely to happen since we have a few persistent trolls continually making new accounts. If the mods are unable to ban the troll quickly, the upload limit will prevent that account from shitposting. They could still make another account, but it would take more effort on their end.
However, there is another way to abuse the system. A user may upload a bunch of posts that are of decent quality but mark them as deleted so they can exceed their upload limit. If someone else comes across it, they won't be able to upload it and send it to the modqueue, meaning it is less likely to be seen by Approvers. So either Approvers will need to go out of their way to find and approve them, or more honest users will need to use three of their own upload slots to appeal them.
What if we add a penalty? If a deleted upload takes up one slot like it would if it went through the modqueue, then it would give some level of protection against bad faith mass uploads. However, the uploader will not be given lower penalties then what the system currently imposes, so it won't actually make things easier for them. The only way to give the regular users the benefits they want is to completely break our checks and balances.
If it's only provided to Contributors and above, then the penalty issue becomes moot since they have unlimited uploads anyway. Thus, the only benefit would be reducing the burden on Approvers, but the change in the number of posts in the modqueue would likely be insignificant unless the Contributors are uploading a large amount of low-quality posts, which they shouldn't be doing anyway.
Ultimately, allowing such a feature would undermine our methods of managing the flow of bad uploads and/or push the burden on someone else. At the very least, it should not be made available to users below Contributor level.