The worst part of its foundational issues is most of them were conscious choices made by them to attract a hyper normie audience, the kind of people who have FIFA and CoD as the only two games on their shelves and evidently it worked to some extent, but can you really rip apart all that foundation to lose millions of potential players with the hopes of getting millions more people who have already decided they no longer wanted to play your game?
In a perfect world, they would have already cancelled the expansion and just moved on to the next game but the greenlight for the expansion already happened by the time they got millions of pre-orders, but how much can they realistically fix on a shaky foundation?

I'm still playing the game but there's very little hope. Every weapon has to be reworked but at best they can pull a Frontier and give everything a second toggled moveset in return for deleting Focus and the magnetic attacks that don't actually work half the time anyway. The balance curve for the expansion needs to exclude the mouthbreathing players that they balanced the base game around. The story has to be minimalized but they probably got all the expansion story mocap and half the voice acting done before the game even came out.
There's just a lot of mind-boggling things in the game they should have caught when the game first came out, and now they're just straight up having to mass-buff some weapons so they can keep up with the desperate need for increased difficulty they're adding in these band aid fixes, the GS change list is still insane to look at.