Just gotta say this: while most of what you guys are saying would make perfect sense to most of my group- 80% are programmers- its been mostly impenetrable to me. Then again, I'm a "turn it on & lets go" guy. The more work you make me do to make the product a comfy fit for me, the less happy I am.

Yeah, there are plenty of bad rough human factors considerations in there. OTOH I argue that the very fact that 4e requires a CB with 26 different feat categories is telling us something about the design of the game itself...
Totally avoidable by using AJAX to round trip the important bits of data behind the scenes. To much 'AJAX' ends up as cludgy solutions where huge chunks of data are passed backwards and forwards, and additional rendering is required at the front end again too, but between intelligent cacheing and careful use of AJAX, there is no reason why an HTML/js app would see that kind of lag (unless the server(s) are not being kept up to spec for the usage, of course!)
But intelligent and careful use of AJAX is hard. Whereas roundtriping back to the server or using something that's already there in jQuery or the AJAX toolkit (which will pass around a lot of data if you're doing something complex) is pretty simple.
One thing that would help a lot would be improving the logic of their Suggested / Suggestions lists. For example, Human Perseverence should NOT be suggested to someone who has already taken Resilient Focus. Conversely, someone who has taken Two-Weapon Fighting is likely to want Two-Weapon Defense.
The really interesting thing will be to see how well they use the feedback from CB to improve their suggestions. Just as Pandora uses the data from the Music Genome project to determine what type of music I like, WotC may eventually be able to predict what options I am likely to want for a character. This could be based either on clusters related to my previous choices for the character currently being edited, or even on all of my characters. For example, it's possible that I take Melee Training (X) for all of my low-Strength characters, where X is my highest ability score.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.