Yetter you last post is the same reason that DSMs get a bad rep., cheap easy to mod cars that get in the hands of the wrong people and they complain when it goes wrong because of the lack of maintenance.
I am impressed with your knowledge about rotaries, but you are completely wrong about DSMs and 3Ss, We had a local make over 500 DD awhp for a year on a stock bottom end on a 3S, it made 700+ before being sold, 3S are just bigger more expensive compared to DSMs and have the same problem.
It seems like you have had a bad experience with 6G72, but I can honestly say I don't think its the motors downfall there are plenty high mileage 3Ss to prove it and running a motor dry is never good.
If you are on a 3rd longblock, its safe to say something is up and it might not be the motor.
BOT: The only reason I am not doing a 4G swap is that I already have one in my talon and I have always wanted to build a v8 car and this is my chance.
Bang for buck these motors are hard to beat and if you know what you are doing you will have an amazing car, I say stroke the hell out of it, T-56, and bottle. Throw as much at this setup as you can as you are eliminating the weakpoint in DSMs, the drivetrain.
Good luck.