Sorry, but it's not an issue with Lightroom or ACR either. I use Lightroom workflow for all my different cameras including the A900.Hi Ben
Pleased to be of service.
I hear you about the RAW converter. I use Aperture, and have exactly the same feeling. If it isn't good enough with a particular camera . . . then I won't use the camera!
Noise, especially in the sky, is an obvious characteristic of ACR conversions. It's certainly not an issue with Aperture.
Here's a cull shot as demonstration. 24-70 @ 55mm ISO 100 ... directly from an untouched A900 RAW file no PS anything ... not even sharpening for web. then a crop of the sky ... plus a solid color using thr color picker to match as a control when looking for noise ... of which there is none.
3D is there also. See the dance shot attached: 85/1.4 @ f/1.7 640 ISO on the A900 which I see with all the lenses depending on settings, etc. A function of the micro contrast separation of tones and rendering of detail ... without the AA smeared pixels from my former Canon gear.