Ride for you may have improved a lot, but what about your equipment. It is still absorbing the bouncing and jouncing from the rough ground.
For single set of tire ruts, it is easy to smooth out, just disk and drag or use your tiller to loosen up some dirt so you can use the FEL to back blade it. Rutted areas don't need any more dirt as the ruts just displaced the soil, so it just needs to get the high sides back into the rut.
Sorry to say that for totally rutted up or otherwise rough areas, disking and dragging then reseeding will be about all you can do to it. In the long run though, this will save your back and your equipment plus cut down on future mowing time.