For Elsevier, we have a cap on the number of accounts we can distribute per stream. Ideally we should be able to waitlist individual collections rather than the partner as a whole.
This touches on something we've been discussing more broadly, that perhaps we should be having users apply to 'collections/streams' rather than resources. The behaviour for partners with one collection (i.e. most of them) would remain unchanged, but this could solve a number of issues with the behaviour around applying for collections.