I've never been directly involved in an administrative hire (thankfully). But I didn't think that these jobs typically came with any additional perks other than the absurdly high salary that typically accompanies the job. I could be wrong, that's not uncommon.
The Dean theoretically controls the budget of the college, to some extent, and if the new Dean wanted more latitude or power or ability to make change, it would be with the college budget, right?
Here the typical administration ploy when planning an outside search for a new dean is (1) freeze the hires in the college for two or three years while a dozen people retire or leave so that (2) the new dean is promised the ability to hire ten new faculty in the first year, which (a) allows him/her to dispense favors to some of the departments that are pleading for someone to fill their empty line while at the same time (b) the higher administration can permanently retrieve for its own uses the one-sixth of the college's usual budget for faculty hires (because only 10 instead of the missing 12 are replaced).
This fits what I've seen too. Admin likes to provide some largesse for new deans so that they can secure vassals and be seen as a champion. Our last one was knee-capped upon arrival and never gained the esteem necessary to lead.
You have left out the most significant source of the budget sweep: and all 10 of the missing 12 lines are full profs replaced with entry-level assistants.
entry-level assistants, at that. I don't think I've ever seen a senior hire in our college of letters, arts, and social sciences--but then we're an MA-granting institution. The assumption here is that a certain percentage of post-book scholars is only a requirement at doctoral granting institutions. Entry-level is the only hiring we do.