The video below is an short interview with Battlefield 4 Lead Core Gameplay Designer Alan Kertz (@Demize99), in which is discusses Battlefield 4 weapon customization while walking through his examples on-screen.
While there is not a significant amount of new information to be garnered from this, it is nice to get information like this from a designer first-hand to really get a feel for the intentions behind their design. He shows customization of both primary and secondary weapons (confirming the 1911, for those worried it would not be in Battlefield 4). He also discusses vehicle customization briefly, including adaptive cammo. A special takeaway from his discussion of gun cammo is, whenever a cammo is unlocked for any weapon, vehicle, etc., it is unlocked globally. Therefore, you no longer have to complete some strange assignment to unlock a cammo for only one weapon, as we did in BF3. I know many will welcome that change. It’s a small thing, but I also like that you can rotate and view your weapon or vehicle in the weapon customization screen to really get a feel for how it looks with the attachments and cammo you have added.
Alan also provides a very nice explanation of the tier reloading they have implemented in Battlefield 4. I am really happy for this, as being forced into the full reload animation when you already completed half of it before switching to your sidearm was annoying (albeit easily ignored after some time).