Might and Magic 1-8. I'd like to see the first 5 in basically a modernized Xeen engine, with the latter games' mechanics (except keeping the extra classes like Barbarian and Ninja). 6-8 just modernized period.
Phantasie 1-3. These are some of the earliest gaming memories I have (C64 versions), so while truly ancient and mostly unknown they hold a fond place in the void of entropy that is my heart. Given how simple they are, I'm not sure how to update them, and keep the same feel.
Wizardry 6-8. Again, unified into a common engine and mechanics. Note the theme?