For instance, should we have a way to specify that the tag
I almost suggested that synonyms could be automatically created when they are hyphenated versions of two existing tags - but as soon as the 't' language gets going the t-sql badge would look like a synonym of t and sql. There will be many more examples, which suggests that synonyms need to be set up by people.
I think that synonyms seem like a good idea, there is an implication for badges - but I don't think its a bad one.
In Jonas's comment should the many android sub-tags allow someone to earn an android badge by combining the votes for android-widget and android-sqlite?
There was this question asked last year with good points that got no answers - perhaps this is a trickier implementation than it looks at first glance.