First off, I LOVE the plugin...It's awesome, great job.
As far as wish lists/eye candy: You should play with extjs for the web layouts of things

. Some for the layouts allow for easy customization up to the user (well, except it would not save so you would have to change it every time, unless you save it to cookies..but even then it would only apply on the same computer)
Overall just a more eye-candy gui look to it...instead of the text representation of things, make it more wow-looking.
Player class icon is great, but maybe make it more like the wow player nameplate with Health and Mana/Energy/Runic Power/Runes display,
also maybe some stats like min/current/max in text or as an overlay on the image bars
Similarly for XP, have it as a bar as well as text (I agree that text is beneficial to really see how far you've left to go)
Maybe add the Rep display, to whichever rep wow is currently tracking in its bar (useful for grinding rep profiles)
Type of loot -- gray, white, green..and more importantly Blue/Purple counts (maybe even links to wowhead

by item id?)
Along the same lines, set a specific item(s) you are grinding for (ie pet, purple drop, tradeskill mat, etc) and have a count(with a wowhead link?) of loots of that item displayed rather than lua commands to open bags and squinting to see if you have it.
Or maybe some icon you can click to view your inventory...should be easy enough (thought possibly resource/time consuming and not very mobile friendly) to loop over all bags to get item IDs..and maybe bring over the images from armory or wowhead.
As someone mentioned, allow different update intervals.
What I'd like is to also be able to update stats and images at different intervals.
Say 2 seconds..or real-time, for stats, map and HB feed and maybe 5-10 seconds for the screen image.
Keep up the good work!