As someone with significant time in every Battlefield except for Hardline, 1943 and 2042, Bad Company 2 gets jerked off a lot so I don't think it's a hot take but I really think it had the perfect class balance that actually encouraged a lot of diversity without diluting too much.
>Assault is for assaulting, you get the stock standard assault rifle with a grenade launcher to make destruction and punch through obstacles, and you can dump ammo boxes to keep your team in the fight
>Engineer has heavy vehicle focus, blow the enemies' up, support your team's, also vehicles aren't just something that exists for a few token minutes before it devolves into only gun battles
>Medic is self-explanatory but also gets a machine gun giving them the ability to provide a sustained volume of fire, moreso if they hang around assaults
>Recon is the obvious sniper class but can also augment their team's approach with motion sensors and mortars, also no going prone in BC2

The open weapons system just makes BF6 feel like off-brand COD, the alleged weapon perks/differences are basically trivial outside of recon using sniper rifles so almost everyone is running around with the same weapons. Maps, even for the bigger battle sizes are too cramped because they want basically near instantaneous spawn-to-engagement times, and basically funnel everyone into the same death fields. Eventually we'll just devolve into Metro/Locker murder hallway brainrot because it's clear the only longterm strategy is just trying to get an audience that thinks BO6/BO7 are too fast-paced rather than make the case for Battlefield in its own right.