Here's a couple things that I think would make the form better/more fun, while still being defensive-focused and armadillo-y.

Roll. Give them the roll skill to move around while retracted. Out of combat, it'd just be movement.. pick a direction and roll that way. Out of combat, it'd just be a random direction (similar to flee). Bonus points if it moves multiple steps in a given direction. The big benefit of this is not having to retract to move.

Scream. There's a real life animal called a "screaming hairy armadillo". It screams. I think this'd be cool as a room deafen skill. Maybe it can only be done while non-retracted? But it'd cause anything in the room (non-group/cabal) to attack the armadillo regardless of if the deafen was successful or not.

Forage. It's kinda what armadillos do. It makes more sense for them to have this skill than not have it.

Swim. Everything I found about Armadillos makes a point to say they are surprisingly good swimmers. I think it'd be cool to give them the ability. Obviously they shouldn't be amphibious, but maybe the ability to travel on the surface of water without flight? Possibly even a last breath-type ability where they can spend a short amount of time underwater (maybe a 1-tick or 0-tick timer).