Previously, expression-requests tag was merged into phrase-requests tag.
Pertaining Meta post:
What are [expression-requests] tag for?
In that respect, expressions tag should be merged into phrases tag also.
Additional small request: It would make sense to rename expression-choice tag to phrase-choice for consistency.
Note: I've tried to add expressions tag as a synonym to phrases tag but it doesn't work like that.
https://english.stackexchange.com/tags/phrases/synonyms
Error message:
Failed to propose synonym:
Reverse synonym expressions already proposed on the tag expression