Mass Editing Tags?

I have a lot of tags from importing my categories as tags. Now, its a mess and with over 250 posts on my blog it is a tedious mess to fix.

Is it possible to mass edit the tags, perhaps via checkboxes, similar to the setup for categories?

Ideally, I think it’d be nice to checkmark the posts to edit for tags and then type in what tags to put in them or in my case to remove.