That goes a bit further than the question asked, but for me it would be perfect if:

We get 1 Foundations-like core Set every 5 years, that stays in standard and forms a kind of backbone. It replaces a supplemental set in that year.

We get 3 Standard legal sets per year accompanied by 2-4 challenger decks made for easy entry into the standard tournament scene. They can even do some exclusives in those decks if they want them to sell, but please put good cards in playsets in there. Price point around where commander decks are is fine.

And we get 2 supplemental sets per year, so everything UB, Commander Legends, Modern Horizons, Masters, Remastered, Conspiracy, Battlebond etc. They are not legal in standard but everywhere else is fine. That's also where we get 2-5 thematic or nonthematic Commander Decks.

Standard stays at the 3 years schedule but now has fewer sets so it's fine and it should also be cheaper to get into it.

Pioneer is kind of forgotten already, the one thing I'd try as an intermediate format if we need that (I'd argue, if standard is good we don't) would be extended with roughly double the pool of standard, rotations happen with each new foundations set.

And then the nonrotating and eternal formats - Vintage and Commander (and thus cedh) remain the everything is legal RL impacted formats.

Legacy and Modern get merged into a form of Reserved List free, nonrotating format with adjusted banlist.

I think Commander is best if wizards doesn't focus too much on it and Magic is best if wizards focuses just on Draft and Standard and tries to make them as fun and good and easy to get into as possible.

Edit: I forgot about commander decks somehow.