Thank you for the good responses (also the personal ones, even if I prefer public). Yes the offset is to 'press fit' a programming connector in the holes, without soldering.
Let me know what you think now and if you are interested.
I know not everybody thinks the same, since I got different comments and sometimes even contradicting. I mostly used the comments I got from two university employees and from people interested in the board. This resulted in a slightly smaller board, to fit a certain housing, The Sparkfun 16x2 LCD fits directly on here (yellow outline) and the drill holes match. Digital and analogue ground are 'separated' now, and there is place to mount tact switches for use in the front panel. The space limitation also resulted in stereo jacks on both sides of the board for the audio input and output.