Before asking for fancy stuff, I would like to focus on bare essentials,
1. A basic eyedropper tool - something that I can move around the image to see what the pixels values are. Our eyes play tricks on us and sometimes our monitors shift but numbers NEVER lie. For image editing the ability to see the pixel values is loike having a compass when lost in the wilderness. I find the lack of being able to see pixel values the most frustrating when trying to make final adjustments in SNS. The ideal situation would be one that has dual readout just like in Photoshop where one reading can be set to RGB while the 2nd can be set to LAB. But a single, simple, RGB readout would be a major help.
2. The reduction of Chromatic Aberration would be a huge time saver. Removal of CA is necessary for results which are intended to be printed at medium and large sizes or whose destination is a a high resolution file. Pre-processing RAW files to TIFF is a huge time burden and along with it come challenges of data loss, data clipping, color shifting, and other issues. The automatic CA removal option in the Lens Correction Window of Adobe Camera RAW 7.3 or greater is the benchmark. However, any significant reduction of CA is better than nothing.
Cheers, Murray