I think AC is a real gem of a Sim but, it's too bad Kunos didn't build on that model further. It's pretty clear (through mod'ing) that the overall game-engine has more potential than the developers utilized. AMS2 is progressing decently but, I have concerns that some physics issues in the Madness engine may be extremely difficult to solve. Still, I think Reiza will make the most of what it has to offer in time but, AMS1 also sets a high bar to meet. I'm not sure any of the other titles could replace rF2 in the way it satisfies, or draws us in. I might consider iRacing a strong contender if not for the pay model that doesn't suit me. It too, continues to evolve and grow over time, and certainly has it's strengths.