COD on Game Pass makes little sense unless you already have Xbox and Game Pass. Most people playing COD (Multiplayer) will be doing so for longer than 4mths which then outweighs the cost of buying it outright (and if it's physical you can sell it when you're done too). Warzone is already free and I don't think Single Player has been enough of a draw since 2019. At best it's a small value add for the plan, but I doubt it'd move the needle enough. If you're on PC or PS5 there's basically no reason to move over to Xbox for COD.
The reason to move over remains big, high quality exclusive titles. And when it comes to reasons to sub to GP, I think they're all there already, it's just not enough of a draw to make it truly sustainable in the long term.
Game Pass should have been a smaller, modular add-on to Xbox Live from which you can play XB/X360/X1 titles + select new titles kinda like PS Plus. All they've done is devalued their games by programming the average Xbox player to expect everything on the cheap. Now there's no going back without backlash, they're just backing into a corner constantly..
I think Xbox needs a completely fresh start with a new team, they need to rip the band aid off and model everything on how they can move forward in an optimal way, rather than by trying to make it work with their hands tied behind their back. They're just gonna mosey on in a state of mediocrity otherwise.