First of all, I just want to say that your guides are great and you continue to amaze us with new guides and updates all the time. The service provided couldn't be better.
However! I would like to see the DugiGuide (the main window) become more inviting. I know that lots of people want it to be as small as possible but I'm one of those people who actually wants it bigger and more.. well inviting to use. Right now you can see through the window and there are barely no frames to speak of. I'd rather see the background of the window become a parchment and the frames become the regular "WoW" -theme frames. Perhaps a setting could allow the user to change the opacity of the window but let it be a setting.
I'm sure that it would be possible to have a setting to either run this "advanced" version or the current "lite" version.
That's about all as far as graphics goes. Now onto the structure of the window. Currently you have every guide as tabs. This works.. fairly well right now but what if you add another guide? The tabs will get smaller and smaller. I'm sure you've already had to redo the tabs in order to make room for everything. I propose a sort of "splash"-screen which would work like an index-page. From there you can perhaps have a drop-down in a corner to be able to fast-navigate to a certain guide(e.g. Dailies & Events). The index could also have an alternate way of navigating by having large buttons that represents each guide. So clicking the Dailies & Events button would take you to the same page as the drop-down would.
The index page could serve other purposes also, greet you the player, have a list of currently active guides, etc. You could even place a "Search" field where people can search for a guide and instantly be able to go to it and "activate" it.
Each guide-page(e.g. Dailies & Events) could also be more aesthetically pleasing with a better structure and layout(instead of just "-------Durotar (level XX)-----" -styled categories) so we can easier find the correct guide and get a better overview of what's available - not that it's not easy currently but you get my drift.
With these changes the guidebutton(when the mainwindow is closed) would have to be slightly changed aswell. Having 2 buttons would be enough. Button 1 would simply "expand" a little guide-window which could be a "lite"-styled window where it would say the current guide and the current step and what to do in that step. This expanded window would get an additional 2 buttons, in form of arrows next to the text where it says the current guide. This would allow you to quickly switch between activated guides without having to go to the main window. Button 2 would take you to the main window but instead of loading the index-page it would load the current guide's page - assuming a guide is loaded, otherwise it goes to the index-page.
Of course on each "page" in the window you should have a "Go back" buttons, the usual do-da's.
Anyways, something I thought about. I don't know if my idea of how it should look is possible or would be appreciated but nontheless I think the current guide-window needs a major overhaul!! Both design/graphics -wise aswell as layout/structure -wise.
Hope you found it at least a bit useful