They will have a hard time making the argument for hardware, unless the hardware is part of a complete kit that includes liquid, like the disposables or cigalikes with pre-filled carts. I don't believe the FDA forces people to submit their designs for "water pipes," you know, the glass ones that are supposed to be used for
tobacco smoking.
As for the liquid, unfortunately they will probably consider every flavor, every pg/vg ratio, and every nic content as an individual "product." So let's say your favorite vendor offers 0mg, 3mg, 6mg, 12mg, 18mg, 24mg and 100%pg, 80/20, 50/50, 30/70, 100%vg. That's 30 separate product applications per flavor, multiply that by someone like MBV with ~200 flavors and that's a lot of application fees. Depending on what the application process is like and what the fees are, I foresee our choices in liquid getting much much smaller.