Tag wiki edit suggestions can be
Improved, same as other posts.
But you can only
Improve a post if you would have the right to edit it unsupervised. For questions and answers, the requirement is the same as approving edits: 2000 reputation. For tag wikis, you can approve at 5000 reputation, but you need 20000 to make your own unsupervised edit. So as long as you're in the 5k-20k range, you can approve or reject tag wiki suggeted edits but not
Ok, the system could be changed to allow you to suggest a second edit. But on Stack Overflow, where suggested edits require two approvers, that would be fairly complex:
- User A comes along, suggests an edit.
- User B improves the edit, suggests a second edit that depends on the first.
- User C improves A and B's edits; or maybe approves A's and reject B's, or maybe decides that B's edit is great but A's stinks, ... The set of possibilities grows quickly.
Would the complexity it really be worth it? Can't you just approve or reject and wait a bit? Tag wikis don't require the edit fluidity of posts, a delay of a few hours won't hurt.
Complementary notes for sites other than Stack Overflow.
On sites other than Stack Overflow, suggested edits requires a single approver; so the
Improve button could mean “accept this edit and suggest a new one”. But since you can do that in sequence anyway, it's not particularly useful.
On beta sites, the reputation requirements are 1000 for normal edits, 1500 to approve tag wikis, and 4000 to edit tag wikis without supervision.