Actually I think the border between skirmish games and role-playing games is blurred. There is no clearcut distinction, as shown by the fate of OD&D itself (originally but a supplement for Chainmail). For me, a role-playing game is one where you can RE-USE the same character from a previous game session. Heck, you could even role play your squad leaders with Avalon Hill's Squad Leader!
:focus:
Maybe one thing that can be 'learnt' from skirmish games is that clear combat rules are a plus, and that the possibility of laying out clearly combat on a grid- or hex-based map is a plus, as role-playing games DO tend to include lots of combats, and you don't want those to slow your game down.