Recommendations have been a part of admin applications for a long time, and I feel like there's never really been a point where recommendations were actually part of what made a good admin or senior admin applicant. I feel like it's always been a way for admins to hand out brownie points to people they like, which isn't necessarily a bad thing, but the fact that you actually need recommendations to apply is a good way to promote "suck-up" behavior rather than qualities that we actually seek in potential administrators. The recommendation system can also bar potentially good administrators from creating an application, as they don't necessarily need to form strong bonds with certain administrators to be a good administrator themselves. These same issues apply to the senior admin recommendation system as well, and they also occur in conjunction with another issue that RedEastWood mentioned in another thread: there are very few admins of a high enough seniority to be able to give out enough recommendations to meet the minimum requirement.
One important use of recommendations that is common on applications is to put emphasis on positive feedback provided about an applicant. This is important, however, I don't think there actually needs to be a recommendation system for this to happen, as admins can still express that they strongly support the candidate without the system in place. Another use of recommendation system is that it is an easy way to filter out applications that obviously don't meet requirements, but I think most of these applications have some sort of other issue that would immediately cause them to be declined. Even if they didn't, I still think that these applications would be quickly denied anyway.