Many of Pat Gainer's ascorbate developers had fairly high pH. One of Relistan's innovations was to formulate that style of developer but with a lower pH. In his article linked below under the heading "What does it look like", he explains the effect of PC-512 on grain.
It's open to debate, but there may be advantages to using a developer that avoids sulfate, such as enhanced acutance.
https://imager.ie/a-simple-phenidone-ascorbic-acid-concentrate-developer/
Thanks
@bluechromis for the comments and link
Out of curiosity, how does PC-512 combat grain without having the sulfite?
There are a lot of factors that contribute to perceived graininess in negatives. At the top level these are set by the characteristics of the film, of course. Then within those confines the developer can control (fine tune) some of the properties through: control of the pH, control of fog, and by managing the emulsion (e.g. expansion) or access to development sites not directly exposed.
Sulfite was used for this in part because it is already used in many developers as a preservative, it has a noticeable effect on pH, and because it is a mild solvent (exposing more development sites) that also works as a mild anti-foggant.
If you can control the fog without sulfite, and you don't need it a preservative, the question then remains whether or not you can achieve similar results of perceived graininess without compromising acutance too much.
There are so many variables it's hard to describe all the effects and interactions (and that's why we have so many developers!) but what I did was get the pH right down low like XTOL, but that doesn't control the fog. What did control the fog was getting the ratio of the developing agents right. And that also had a noticeable effect on reducing perceived graininess. And there additionally is some positive grain effect of the interaction between ascorbic acid and borates that is sort of acknowledged but not yet explained well publicly (I am sure Kodak knows). In the end the effect of sulfite being added is really small when everything else is working right. But sulfite doesn't mix with glycol, and sulfite in water is much worse at preserving a developer than putting it into glycol.
My view is that Kodak largely used sulfite in XTOL because it allowed for cheap and easy shipment of a developer to be mixed into water, acted as a preservative in powder form in the event of mild water presence, and it produced an image that looked a bit softer, and more like D-76.
Hope it helps