A good way to get more potential in your army is to put some of the Grunts in the 2nd combat group. In exchange put the most order hungry units in the first combat group because you seldomly use all orders provided by the link team for the link team itself especially with long ranged weapons in it thus the other units will benefit form these spare orders, like, well, Van Zant
And regarding Van Zant and his Paratroopers:
I personally think the Mavericks are more efficient than the Airborne Rangers you basically get two orders more per Maverick and Smoke. But don't wait to use Van Zant! If your opponent has vulnerable, and expensive, or annoying troops in his DZ kill them with him.