For me, I'm not paying €70 for just the campaign. The multiplayer needs to seriously hold up as well.
In that regard, I'm highly skeptical of their claims of big, open maps. For me, the only reason that MW2019 worked fairly well was because they used small maps, which nullified the major weapon design mistakes they made and which WERE highly tangible in Warzone. If they were to go to big maps again, they'd fall for the same pitfalls, in my opinion.
MW2019 was good, but it failed at most things that made CoD4 and MW2 so good - and they are almost unable to reverse those decisions now, because of the direction that shooting games are taking. The important thing is whether they frame the rest of the game well enough to compensate for those mistakes.
Really, I think they only have three choices; regress to an earlier, arcadier MW style (which they won't), move forward massively to where they rival something that's vastly more realistic and detailed, like Tarkov (which they couldn't even if they wanted to), or try to navigate the midspace as well as they could.