Just a little idea I had, think it would be fun. Comment your favourite systems and the rest of us will give you recommendations for something that could possibly fit your interests.
Have you looked into Strike! RPG? Setting agnostic tactical combat on a grid heavily derived from dnd 4e but with all the fat stripped, leaving a very light, low-math, simple to run combat with a ton of depth but low number crunching. All that is paired with a narrative system that's very intentionally kept light and with intent to get out of your way.
If you're looking to run something where the PCs are a crew of specialists with distinct roles, this might be worth considering.