The startup screen
is necessary. It gives the user feedback, like 'yes, I'm running' while it loads the data from the registry.
Actually the blue color(s) are "natural windows colors"... Windows XP's blue interface uses the same colors in explorer (e.g. for instance the sidebar in 'this computer').
I'll agree that the icons aren't as good as one could wish - but I'm not much of a graphics artist, so not much I can do... I'm open to user-created material though

The welcome text should be replaced with what now? Please elaborate

And the flags... I'm actually quite happy with my "home-brew-flags" in the newest beta, and 'stealing' other's opens up a whole can of worms with license and stuff...