Fixing Anti-Aircraft units

As it stands, nobody uses the AA units, and probably 95% of them ever used take place in Ultimate WWII as starting units for Germany.

So here is my plan.

First we must compare them to infantry. Infantry get 6 defense while AA gets 3 defense. However, against air units, AA gets an added 8 defense. This makes AA have a grand total of 11 defense against air units. But AA are worth 180 while Infantry are worth 70. Therefore, two Infantry have one more defense point than AA and a cost which is 40 less than AA. So unless your enemies are all confirmed SM and you have lots of money, AA is useless.

So how do we make them usable? Easy. Cut the cost of AA from 180 to 90 and cut the defense bonus by 2. This way, AA has a total of 9 defense against air units. Now let's compare.

At the beginning, it is probably worth more getting infantry still. However, as time progresses, it becomes more worth while to buy the AA. At the 8 unit maximum reinforcements per city in one turn, AA has 72 defense at a cost of 720. For infantry, they would have 48 defense and 560 cost.

At the same cost of 630, AA has 63 defense while Infantry has 54 defense.

This would ultimately make AA much more useful and used while still more costly than infantry with better defense.

I also think they could be slightly better for their cost.

Infantries will always be better comparing cost (don't take imp militias into account lol). That shouldn't get changed.
Imo, it is fine as it is, AAs are only good in high fund games or in a rush in a neutral country when the other one is SM (Ukraine-Volga rush on RC for example)