As you probably all know, in order to nominate a tag synonym you need and answer score of 5 or more in the tag (and 2500 rep.)
For very large tags, say c++, this seems low. It's not hard to get 5 answer reputation in such a large tag.
For very small tags, say otapi, this may be hard to achieve. I happen to know a reasonable amount about that tag, and want to suggest it is a synonym of toolsapi, but I don't have the answer rep yet. Given the size of the tag waiting to get it might take quite some time.
Long-term, we need to drop the idea of a fixed score, and grant or deny this privilege based on the size of the relevant tags. A score of 5 is waaay too low for suggesting, say, ruby as a synonym for c#... But as you note, it can be too high for very niche tags.
What we won't do is drop the requirement for some experience with a tag entirely.
Given I've run into this several times now, that sounds like a good feature-request to me :) Or to put it more seriously, several times I've wanted to suggest synonyms but been unable to, and the topics have also been small enough that waiting to get enough reputation takes an unreasonably long time. I've made a couple of tag synonym requests in meta, and it feels wrong to have to do so, when I'm used to being able to directly take action on the site.
I'd like to suggest two possible changes to the system:
- Make the minimum answer score a function of the tag size.
- Take into account reputation in related tags. For example, otapi and tools-api are delphi questions; if I have plenty of rep in delphi perhaps I should be able to suggest synonyms for the first two too.
I would guess the first is simpler to implement, but I suspect the second would be more useful, so I'd vote for that if it's reasonably possible to implement.
In order to keep the requirement of some experience with the tag, perhaps for small tags an upvoted question or two would be enough.
This problem has come up before in other forms:
- Can trusted users be trusted to suggest tag synonyms without a score of 5 in a tag? (on smaller sites, not Stack Overflow)
- Can we allow 7.5K users to suggest tag synonyms without a score of 5 in the tag?
- Relax tag synonym voting rules and a few other duplicates.
The above quote ('long term we need to...') comes from the first of those links.
Some changes have been made, but the issue of what happens for small tags remains.