If I had the negatives, I estimate I could get about 5-10% more detail, color fidelity and dynamic range. 10% at the outside; probably being generous. I'm basing that on the difference between the best looking official shots I've seen and my best attempts at them. But there are many times in which I'm outperforming the official releases (like some of these Reliance clips) just for the simple reason that I give a shit, know the material, have tools specifically designed for this film, and will take the time and go to the lengths necessary to get it right. Mostly though, it just bothers me on principle, how far I have to go; I'd rather be spending the energy finessing the negative than trying to turn a print into one, that's all. But it's an evolutionary process. Just last week I stumbled upon a refinement that's giving me another couple percentage points of a quality bump.
I'll go on the record and say this: if the Reliance restoration is a 4K OT, there will be sections better than I can do, and sections for which Legacy is better. Also Legacy's color will likely be more historically accurate end-to-end. I can almost guarantee that.