There are historical examples of users unilaterally doing an action en masse that was viewed as problematic, to the point where either the Meta community creates a formal procedure or where the system is altered to alert someone...
Yet there are other examples of the exact opposite:
- animuson
- Bill the Lizard
- Shog9
- Robert Harvey
- and I'm sure I'm missing some
But in concrete terms, if the user has more or less the same accuracy as the community at large at closing questions (closed questions that were reopened without edits/closed questions), I don't see any problem with this. The moderator could just as well go through the close queue on the moderators tools and would achieve the same thing... just without filters and other nice quality of life improvements that the review queue includes.