The spacing is something I noticed, too, and I agree with the umlaut thing. The small "e" looks a little awkward - like it doesn't quite know if it's an "a" or "e". You could try making some tweaks to it. You could also see if adding an extra space inside big V and Y would make them more aligned with the rest of the letters.
I'm sorry, this probably sounds like some font snob nitpicking. On a more positive note, I absolutely adore the small "z"! Real solid work for a first experiment.