Something like that would be great!
Most users will probably be fine with the normal SRS pacing, which is great. But I think an SRS looseness setting combined with the already existing SRS strictness setting would be perfect for people who want to slow down or speed up.
In the meantime, I figured out a way to do it manually by just going through the review list after reviews are done and bumping each one up a level. It’s slow but better than huge review piles.