DICE's core gameplay designer, Alan Kertz, noted that although they used the Battlefield 3 classes as a starting point, Battlefield 4 will have more custom details when it comes to certain classes role and sub-role. It will feature Chinese, Russian and US variants for each class and each of them will look different on the battlefield.
Alan Kertz also shed some details regarding each of the classes noting that there will be different weapons ranging from high-damage ones that will be harder to use up to fire-and-forget smart weapons as well as some details regarding the support kit. As far as the Recon class go, it will get a much needed boost to mobility in order to get it close to "Spec Ops" style in case you want to go for some behind the enemy lines action. He also games some details regarding the Assault class which will get some changes including a role of combat medic with First Aid pack, med-kits and much more.
In case you missed it earlier, Battlefield 4 is expected to launch on PC, PS3 and Xbox 360 on October 29th in North America and November 1st in Europe while next-gen Playstation 4 and Xbox One will get their own versions as soon as they start selling.