This will definitely be the sweatiest COD to date and SBMM is already heavily tuned up in the beta it seems. It'll be even worse on release because the whales will be armed to teeth with their P2W bundle weapons which even nerfed, are still better than the base weapons. I think users can carry over their skins too, so day one you'll have people dressed up like Barbie and Godzilla running around with their weapon of choice from any one of the 15+ £25 bundles previously bought. I think this could be a bad experienced even for seasoned returning players that haven't played for a while.
Another interesting thing is Activision have merged MW3 with MW2 and Warzone on Steam to form a centralised Call of Duty AppID. They've basically done this to swerve any player count scrutiny for the multiplayer portion meaning they have effectively closed and DMCA'd every API at the expense of MW3 appearing as DLC ironically. Too bad they didn't strategically centralise the entire new era Modern Warfare 2019, MW2 and MW3 into a collective package so users could cross-play maps across games but instead have made a knee-jerk decision to do it just to cover up any potential dips in popularity.