Any open world shooter games like Battlefield series?

Planetside 2

Actually. Battlefield It's not an open world game, if you want an open world you should try Far Cry 3 or 4, or maybe Fallout 3 or 4 if you like survival games. Well, there is a lot of open world fps games, just search for FPS Sandbox games at google and you will see =)

I'm not sure if it it's truly considered an open world game, but you could always play the Borderlands series.

Fallout 3+

How is BF open world?
There aren't many big budget games like that anyway... Arma would have really been your best option.
Open world FPSs tend to be sci-fi or post apocalyptic, not military.
If you're ok with those themes: S.T.A.L.K.E.R., Fallout: new vegas, borderlands and indies like DayZ and the likes.

Open world shooter as in actually open world where you can kill bots/AI, or as in an MP shooter with insanely large maps?

No politics like Russia VS USA, then wtf is battlefield, furries vs sharks?

And ehm, not quite sure what you mean by open world, pretty much any online shooter is open world in comparison to BF. Heck, even CoD.

But seriously, if you consider fighting someone from another country politics, you're not gonna find much games that aren't (I spawn team A, you spawn team B, oh no, we can't be sent in to kill each other! Well, any game that involves 2 teams, and is a shooter, will have that).

CS:GO =D

ghost recon phantoms
medal of honor warfighter
waframe