Despite boats and minecarts wobble whenever they "take damage", armor stands never show the wobble animation when being broken in creative mode, when boats and minecarts do. 

Also, they never wobble when getting hit by an arrow, once again, minecarts and boats do, at least for a very short time. 

Minecarts not only show wobble when being hit with an anvil, they also can be broken with an anvil. Armor stands lack that, despite being made from wood and not iron.

How to reproduce:

1) Go into creative mode

2) Place a boat and minecart

3) Punch both (may require a few tries to see the wobble, it is very quick)

 Both Minecart and Boat wobble when being hit in creative mode.

4) Place an armor stand

5) Punch an armor stand

 Wobble is missing.

This issue is not present in survival mode.

6) Place minecart, boat and armor stand.

7) Get a bow, and shoot all three (again, may require a few tries to even see the wobble happening)

 Boats and minecarts wobble.

 Armor stand doesn't.