OK... commanders are of value in the following situations:
Any city map: The limited view created by the cities make it very easy for enemies to sneak around. It also makes it very easy to ambush an isolated enemy if you are careful. An NA maker greatly increases your chances of ambushing them and avoiding ambushes yourself.
In case of a rush: Sorry, but most rushes I've stopped where located by the guy with the NA maker. If you see one or two blimps moving fast for your base, it's a rush. The NA, though not vital (your eyes and ears work very well on more open maps) can help and spot things quickly too.
When you need to be stealthy: OK... you want to avoid the enemies, well... an NA helps. As pointed out, there's the wheelie MG/NA commander that sneaks behind to strike the base. This is also common in 1 on 1 fights in the war where the enemy has one of these, and goes for either com victory or base destruction. They grab combs and can keep an eye on you, attacking the base when you move away. Even in larger maps, a lone NA hound can sneak behind the enemies easily while your remaining troops provide a distraction.
However, yes, if you use an NA purely for communication purposes, then no you don't need NA makers with the advent of the Party system.