The font issue does appear to be a genuine bug. Can I suggest you report it in the usual way, please.
The reason for the non-appearance of 0.7 is that Maple tries to avoid drawing tickmark labels that overlap. If it finds labels that overlap it removes those that do, maximising the number that it can draw. In this case it is trying to draw tickmarks at intervals of 0.1 but has to remove all but the ones you see. Maple always draws the first and last tick label; 0.7 would overlap with 1.0 and so can't be drawn. Making the plot bigger, or using a smaller font, would allow it to draw all of them without overlap.
David Clayworth Maplesoft GUI Developer