Hopefully some of our friendly neighborhood Devs will notice and be able to answer this...
In PlanetSide, everyone could carry some sort of anti-armor weapon, be it empire-specific AV, a Decimator or Rocklet rifle. AP ammo was an option too. In PS2, I find it more and more likely that only the "Engineer" class will have access to a missile/rocket launcher.
Multiple ammo types will most likely not be available in PS2, as I think SOE wants to streamline gameplay, rather than keep it complicated.
If this is the case, one solution would be to make MAXes more susceptible to small arms fire. However, with all the disadvantages of using a MAX, I can't see why anyone would want to choose being slow, DPS-only and not really that much more resilient in a firefight.
I'm kind of hoping that all classes, except Infiltrator, MAX and Light Assault will be able to carry a secondary weapon, like a grenade or rocket launcher. Perhaps the Light Assault class will be able to have a secondary weapon too, at the expense of not being able to wear and use a jetpack.
The Engineer could have access to more potent AV weapons, but everyone should have access to something that lets them deal with armored threats, at the expense of having to swap weapons should any infantry pose a threat in the meantime.
I think not carrying what might be more useful at the time is downside enough and I hope the AV side of PS2 won't be one of the things inspired by the Battlefield series.