Moving assets between workspaces is something we've had on the list for a while - it'll come quite soon hopefully, and shouldn't be too hard to implement.
If you do have tracks with a lot of edited points that you want to use in another WS, the best course of action now is to just export those tracks in GPX or CSV, and re-import. You'll lose sonar and bottom composition, so it's not a perfect solution, but you would get your edited points which could then be used in a project. Note that if you export with the tide adjusted option, then you shouldn't adjust the track in the new WS.
Half an hour load time for a project? Have you updated to 1.7? Load times are massively reduced (x50 or more). If you have already updated - how big is the WS file on disk, and how many tracks do you have?
Matt