Dgn Preview Handler is very very handy. Gives the user a good way to inspect the dgn in MS Explorer before loading which saves a lot of time. Users can have multiple MS Explorer folders open which is very very handy. Zoom, orbit and pan beats static thumbnails.

What would be good is to extent visual inspection to the non-graphic data in the dgn.

A 'Project Explorer' tab listing the usual PE info would be great.

Extra credit: Enabling drag and drop would be awesome. This would allow the user to avoid having to load the whole dgn just to get say a particular Cell in the dgn model.