i like it! I never attempted a "modern days" map, i'll give a try sooner or later

about the legend, i think you should evaluate the situation: what do you want to offer to the viewer? Is it already on the map? Considering this, you can work on it.

As it is now, your map gives some visual informations: you used colors for altitude, if i am not wrong, so your legend could offer an explanation (a patch of color with associated the altitude range, maybe?).
You should also indicate the scale of the map.
You could even make some differences in city icons, and then explain that the black dot with a circle around indicates a city of more than 500000 people etc. etc. There are roads? If you trace them, maybe there will be differences between them (double line for highways, single for main routes, dotted for secondary ones?)

It's a good map, hovewer!