It's hard to discuss synonym suggestions. There may be multiple viewpoints and confusion to be ironed out, yet all we can do is vote or tediously track down the suggestor and hope they provided contact details. (Or find a random post and comment to them.)
Meta is the right place to discuss synonyms, but you can't find those discussions when looking at the suggestions (i.e. .../tags/XXX/synonym pages).
Similar to the "linked" sidebar on questions, could tag synonyms indicate what Meta posts discuss them? This is slightly different from current use of "linked", principally because it would require working across sites.
Instead, could there be a smallish wiki section on tag synonyms to list links? (And other info? Not sure what would be appropriate there—discussion about rationale would be better in a Meta post.) This would allow linking to discussion from any SE site (e.g. back to a meta.SO post when the same rationale applies to a Webmasters tag).
The automatic "linked" list is preferable, if it can be done across the SE network (possibly only to meta.* sites?), rather than manually (i.e. not) updating a wiki. But it seems the former feature requires more thought (and could be useful in other areas), while the latter could be a useful stopgap.
