* small screens: Krita is meant to be a professional tool for professional painters. That means we optimize for big screens. The minimum resolution to use Krita is 1024x768, and Krita does fit in there.
* Jumping palettes: that no longer happens. Was difficult to fix because we use Qt's docking system, but at the expense of adding optional scrollbars to the tool option palette docker, we managed to get rid of the jumping.
* color selectors: the current set of color selectors has been created from input by professional artists and they haven't asked for an HSB mode. Having a grayscale colorspace mode available for RGB images was much more important for David Revoy. But the artistic color selector offers HSY, HSI, HSL and HSV modes, though, and if that doesn't satisfy you, it's always possible to file a wish in bugs.kde.org -- that helps us keep track of users' requirements.
* buggy effect layers: it's possible, of course, that there are problems there. To fix any problems of which we might be unaware, we need users to report bugs. And note that I've always said in public that I'm pretty easy-going about bug reports. People can mail me with a problem, ping me on irc or enter a bug in bugzilla themselves, that's all fine with me.