I created a suggestion for the tag synonym 'mg.metric-geometry' <--- 'classical-geometry' two weeks ago. However, it appears to have received no votes yet, up or down. Is this delay to be expected? If not, what is wrong?
The tag synonym voting mechanism doesn't really work well for any site but the largest ones. The requirements to be able to vote on a synonym are very high, and the visibility of proposed synonyms is almost nonexistant.
I'd suggest to propose synonyms on meta and have the moderators create them once a consensus is reached. The public discussion usually makes sure that the synonyms make sense, and it is far more efficient than voting on synonyms in most cases.