Well, I'm not a fan of battlemages, using heavy armor. I like the old style mage with a robe and a staff, casting powerful spells far from battle. So yes, robes please!
Of course, with some defensive spells like Mage Armor, Shield and Mirror Image (DnD) as temporary defense so the mage can have a minimum defense and don't die in 1 or 2 hits.
But that's my opinion of course, based on the Wizard style that I prefer to play. If you want to enter deep in RPG style you could use some feats system that a Mage could choose to user Leather/Mail armor, but with a casting penalty, casting time, chance of failure, etc... but again, you are opening a lot of possibilities for the Class, but it can be very difficult to develop and balance, and it seems to me that most part prefer to play the old style glass cannon Mage.