I don't think the GUI is the key. Monero appeals most to extremely intelligent people who also have lots of money (aminorex, ArticMine). This type of guys will be the deciders of the price in the short (1 year) term. The masses come later.
It does help some investors who aren't necessarily comfortable with command line tools and don't want to keep their coins on a web site. Unfortunately even the third party GUI wallets at present require some facility with the command line to install and configure.
Only a basic GUI is needed for this target market, not something that would attract or serve the masses.
Yup, and when the GUI is released (after the prerequisites are met) we can expect the price to make a very large upward swing and bounce around that point. Where that point is is anyone's guess right now. My Guess would be about .05 or so.
BTW Rpietila I also enjoy reading your posts, It's obvious you put alot of effort into them.