I'm not exactly sure that is a good thing. While I don't believe that MS is playing 4D chess here, I do believe that Sony being so hyperfocused on Call of Duty is ultimately going to be seen as a net positive to Microsoft in the end. While Microsoft continues to dangle the keys of Call of Duty upfront, behind them is King, Blizzard, and the entire ABK catalog (both current and upcoming) boarding the bus through the back door.
I've always believed that if push came to shove, Call of Duty was always going to be used as the sacrificial lamb to get this deal through. So far, that looks to be the case.
It isn't a sacrificial lamb though. The IP's biggest value to MS is as a multiplat that comes to GamePass day one and maybe gets Xbox exclusive/timed content.
Taking it completely off PS, especially mid-gen when tens of millions of people own Playstations, just diminishes CoD's net significance while creating a massive vacuum for a new title to fill. Microsoft's biggest benefit is having Xbox be the best place to play CoD, not the only place to play CoD.
Sony knows this, but CoD is the only argument they have. King has basically zero business impact on Sony. Blizzard is a very small number on Sony's balance sheet and far more significant on PC and mobile, where Sony has only just recently even treated that like a viable market for their own titles.
The optimal outcome for Sony is limitations on how MS can differentiate CoD from Playstation, not a promise of receiving CoD on playstation. That means limitations on GamePass and exclusive or timed content. Which is exactly the thing MS doesn't want, because that is the biggest bang for buck they'll get from CoD.
From a regulatory standpoint the valid points of contention, in my opinion, would be MS' ability to utilize ABK's portfolio, specifically King and Blizzard IPs, to build an early advantage in cloud that no one would be able to complete with. MS argues in their filings that cloud gaming is still in its infancy but when Nadella and Spencer both tout XCloud, etc. as a key developmental feature and are spending significant amounts of money and PR time building it the current state of the market should be seen as a secondary consideration.
That argument is rather dubious for Sony as they're the second best positioned entity for that market and had early technology/services there years before MS and failed to develop it, so the best they can argue is that the market will only develop with companies like MS fostering it, which puts regulators in a catch 22 - a market that can only develop via a trillion dollar company monopolizing it in its infancy doesn't really fit any kind of regulatory model. This leaves Sony with only really CoD to paint a clear narrative around, which they've done pretty successfully.
I doubt it'll matter much ultimately but even getting this into contention with regulators v. what has been approved in the past 5 years is a win for them.