The default/limited Arsenal is being switched to the ACE arsenal now that they have fixed a couple issues. It is still a limited arsenal, but you get some of the ACE features worth having; you will be able to search for items, share loadouts between players and you get access to advanced stats of items, including things like true rate of fire accuracy in mils, muzzle velocity, hearing protection, backblast and more. You can also change your Face, Voice and Insignias in the ace arsenal (Including medic patches and soon to come the NAK Tac patch.
To access the Arsenal you will have to interact with it, no more action menu item.