Richard,
You've done a great job unlocking PE's back doors and I am aware that you have found work arounds in PE3 and 4 (I have both of your HE books) - however a few critical features (IMHO) are still missing from PE (3,4 or 5):
- Full color management/proofing - this prevents the use of different working spaces (e.g. Joseph Holmes Chroma Variant sets - designed to manage saturation and control luminance correctly) - see this link -
http://www.josephholmes.com/profiles.html or review his downloadable samples - they are very interesting - the link is here:
http://www.josephholmes.com/propages/Examples.html
(I realize that most PE users don't need/care about this - however I like to have the option to research/experiment - I consider it as part of my overall education

).
- 16/48 bit processing for levels/layers - For some images it helps to preserve the full dynamic range (at least until the most critical corrections are done) - even though we end up printing only 8 bit images.
- Re PWP and Masks - Norm Koren's tutorial see:
http://www.normankoren.com/PWP_masks.html - explains this in some detail - see the discussion of 3rd row dialog box options - re HSV/HSL color space selection; color range masking; masking with similar pixels (fixed or tracked) while painting a mask, masking based on brightness etc.).
FWIW - PWP also allows users to work in RGB/HSV or HSL modes - all in 16/48 bit mode. It also supports full color management/proofing as I described above.
BTW - I not trying to say PWP is better than PE or PE + HE - merely that there are alternatives to PE at similar cost. The PWP metaphor is also distinctly different than PE (no layer support, no plugin support) and has it's own learning curve.
Although it has a great user forum, this not compare in scope to the broad industry support and user base that PE enjoys. IMHO it does offer great value for the $. (I have no affiliation with either product/vendor here).
If you take a look at PWP I'd be interested to hear your comments/feedback.
Regards,
Brendan