I would disagree. BF1942 is still the best game in the BF series. The whole leveling schtick they are pulling is absolutely horrible, the maps are much smaller, and overall there's less stuff to do. No naval ships or airplanes. There are helicopters however, but that's about it and they are as unwieldy as the ones from previous games.
It is also dumbed down. The Scout spots for artillery, but the players aren't the ones who supply it, it just falls from the sky sort of. The engineer and anti-tank are combined. So now you have a guy with rocket launchers, guns, repair tools, and mines running around. The medic is given a fucking machine gun which is ridiculously overpowered for a class which can heal itself whenever it wants to. Oh yeah, the assault is also the one that carries the ammo boxes in this one, so you have the class with the most powerful weapons basically have endless ammo to their grenade launcher.
The game also has far less vehicles in sheer number than Battlefield 2. The leveling bullshit is even worse than in Battlefield 2, you literally start with nothing at the early levels, and there are many many weapons to unlock, not just 1, or 2 with the expansion, for each gun type.
All in all, BF1942 is still the best BF, then BF2, then BC2. Basically, reverse chronological order.
Edit: Just a few more things. Shitty netcode, I have a blazing fast connection and even when connected to servers across the street from me, literally, I have never seen less than 130 ping. If I am not connected directly to my modem then I cannot play since the game disconnects you from the servers instantly. Also, there is no proper player auto-balance at all or something to even ensure people don't switch teams when one starts to lose. Maps also do not change their size depending on the amount of players on it. So if you have a map with 5 people, it will be as big as if you had all 32.