Re: Win10, I'm running it here and never saw any mouse issues like what you're describing. Other annoying things, certainly, but none with Torque so far.
Re: Flight simulators, like @ JeffR
said, it's all about how deep you want to go. I wanted to go deep, and I'm also lazy, ie old enough to realize I'm never going to have enough time to do everything in life I want to do, so highly resistant to taking on new wormholes if it's at all possible to avoid them. This line of reasoning led me to abandon any attempt at actually writing a flight simulator, and instead my attempts are all directed at taming the wild lovely beast called FlightGear (flightgear.org) which is everything I've ever dreamed of in a flight simulator, squared. What I ended up doing (not going to go into detail here, because I know I've done writeups on this already, will find them for you if interested) was hooking up a running instance of FlightGear to a running instance of Torque through a little networking library I wrote, and flying the plane through FlightGear but seeing the results in Torque.
This is admittedly weird, and not sellable as any kind of retail product as is, due to the unwieldiness of running both applications at once just to fly a plane in Torque. But my plan with it is to spend some time massaging FlightGear into invisibility by removing the window and the render, and having it exist only as flight dynamics system. There is already work going on within the flightgear project to modularize the program and make it easier to turn off whole sections of it, so I'm putting that part of my plans on the back burner for now while I see what happens over there. But all of my existing work in this direction is in my MegaMotion public build, on github (github.com/MegaMotion/Torque3D). Look in sim/dataSource/vehicleDataSource. My system is far from ready to use but it might be worth consideration, depending on your goals. To run it you need to use an xml file to tell the flightGear executable to stream out the data you need via UDP, let me know if you're interested and I'll look up the magic syntax.