Is there a way to flag tags for merging? I don't really want to open up a meta question every time to request a tag merger.
(Beta) Users with 1,250 reputation can propose tag synonyms if they are considered to have sufficient expertise in that tag (i.e. have an answer score of at least 5 in that tag), and other users with similar expertise can vote on it. As far as I know, this doesn't actually push a notification/flag to anyone, requiring users (and moderators) to actually check the proposed synonyms list manually for new additions and vote accordingly. If approved, the tag will be synonymed (merging is, as far as I know, a moderator-only ability).
I do check the list on occasion and approve anything that I consider a no-brainer, but given how rarely any non-moderators even use the tag synonym interface it's not something I do regularly. For any tag pairs that aren't no-brainers (i.e. perfect synonyms), bringing it up on meta for community discussion is still preferable.