The best battlefield was...

personally I got hooked on BF4, probably started playing it around 2014 or so meaning well after its launch...played it on PS3 originally then PS4, very fun game made alot of friends playing it and got really good at first person shooters(IMO at least).

Played hardline, terrible game BUT it had alot of new features that were really good additions such as being able to grab meds off of people, grab ammo off support, grapple hook, repels many of which made it into newer BF games including 2042...unfortunately grabbing ammo/meds isn't a thing in 2042, grapple is more advanced but tied to one specialist and the repels are simply set in place on some maps.

BF1 was  huge change and huge gamble but it ran fairly well at launch, not perfect by any means but what a fun game.  Martini henry was so fun, tank play was fun, plane play was fun, gun play was fun, pickup weapons were fun...if I had never played BF3 or BF4 this would definitely be by #1 in the franchise.

BFV was bad, then end

BF 2042 if bad, like worse than BFV bad CURRENTLY, its not to say they can't fix it in time but its not that fun to play and I need to force myself it play it.

I have started with Battlefield in 2016 and I really have to admit that I loved the game. I mean I cannot really evaluate any of the previous games before it, simply because I have not played them or at least I did not play them much. 

What I really liked about Battlefield 1 was the level of immersion. You really felt like in a war running through maps like Argonne Forest, etc. Also I really enjoyed playing with those older and often very crude and experimental weapons - I found them quite exciting. Moreover I personally think that Battlefield 1 was a relaxing and less try hard experience. You could simply have a fun time there, it was way less frustrating than the games coming afterwards in my opinion.

Nevertheless I also know that it had its flaws like random bullet spread, elites, sweet-spot mechanics (even tho they were fun when sniping myself) or suppression causing your bullets to go everywhere. 

Still I enjoyed the game, it felt well-conceived and the design went in one clear direction. It was very casual but it went casual all the way trough. It had its own art style and I enjoyed it a lot. Nowadays DICE unfortunately has taken the role of a copier trying to combine several game directions which obviously does not work out.