Disadvantages

On EN wiki it is already difficult to get anyone through RFA, I fear if this was implemented it would make it more difficult for good contributors to become admins. At the moment they are one of the few groups who can succeed at RFA even as a self nom provided they are civil, have read up on the wiki jargon and give a couple of examples where they would use the tools.

Currently RFA enables people who start as good writers to get more involved in the community. As they finish writing what first brought then here they can start looking at the wider community and if articles for creation, protection policy or the appointment of Autopatrollers attracts their attention they can move in that direction. If we define "senior editors the best we can hope for is that they get delete and restore in order to do history merges. But why not make them admins, and give them the block button if once in a while they might need to use it?

The idea behind Adminship is that this is a set of extra tools for trusted users, and once people have the set they may choose to get involved in areas that they may not have thought of at the time of their RFA. Unbundling and dividing the toolset would make sense if there was a part of the toolset that had historically caused problems with admins misusing it out of inexperience - but the reason why admins have had to be desysopped on EN wiki almost invariably relates to tools they were asking for at RFA. I fear that this extra complication would increase the Byzantine nature of our community structure whilst limiting the effectiveness of some of our best editors.