Umm, A-10s have flown for a long time with FLIR. They don't have it natively, but they always use their targeting pods. See SNIPER or LITENING pod. My pilots did night missions all the damn time. The trouble with the A-10s isn't just the engines, its the airframes themselves are getting old. They are heavily stressed through years of use, their hydraulic systems are a nightmare to maintain, and so on.