I ended up going with the Michelin Primacy MXV4s, got them mounted and balanced this morning, and they are a significant improvement over the horrible Goodyear RS-A's that are OEM. The Michelins have the lighter steering input that I was looking for, are significantly smoother and quieter at any speed over the RS-A's and absorb bumps and road imperfections far better, and all this with little to no loss in traction/grip and overall handling. The car does feel only very slightly softer overall with the Michelins given that they are a premium-touring tire for luxury-sport vehicles and not an ultra-high performance summer tire, but the overall traction, balance, and handling around tight curves and corners is still very competitive with little to no loss in this regard over the Goodyears but with a MUCH smoother, quieter, and more refined ride and a far better tread life rating.
I haven't driven them in wet weather yet, but this was where the Goodyear RS-A's really worried me, they felt like they were coated in grease in any wet weather conditions and would hydroplane even in just normal driving in the rain. I would imagine that the Michelin Primacy MXV4s would have to be better then that after reading all the positive reviews on Tirerack.com which is where I bought them from. The reviews on the Michelins show that they are a true all-season tire and have no problems or issues dealing with rain and snow but I will find out for myself the next time I get some wet weather.
The reason why I asked about a tire with the lightest steering feel is with the OEM Goodyear RS-A's the steering in my G37x sedan always felt a little too heavy especially at lower speeds, and I was looking for a tire that would offer a lighter steering feel and input, and the Michelins did accomplish that for me plus a lot more.
If you want a top-notch premium-touring luxury tire that is extremely smooth, quiet, and refined on the road without a significant loss in handling and grip then I would definitely recommend the Michelin Primacy MXV4. They seem to have no trouble dealing with spirited or aggressive driving, but obviously if you are looking for a tire for maximum handling and grip at the expense of quietness and ride comfort then a high-performance or ultra high-performance all-season tire would probably be a better choice.