I really love the document tracking available for the supported list of programs.
As a designer I use Photoshop heavily and can track projects through the document view with incredible accuracy using client/project codes in the file names.

However, like 99.9% of designers in the world I use many design packages to produce my work.

To support Photoshop and NOT support the rest of Adobe's product range is to render the document tracking system all but redundant for all but a tiny minority of the creative users.

The bare minimum to cover the vast majority of professional graphic designers needs would be:

Photohop
Illustrator
InDesign
Acrobat

If you want to widen the net to capture those designers that design for web add:

Dreamweaver
Flash
Fireworks

Further into the speciality market you could start to cover 3D and motion graphics with things like:

After Effects
Maya
3DS max

(this list can become a little muddy with so much proprietary/obscure software used making it harder to quantify a majority umbrella list)

What are the plans to expand the support list?

Cheers

Paul