Based on the everything I heard when it was being tested, it's not techable. I'm not sure why people keep saying that it is.
Also, hitting any wall in the game does not create a "reasonably situational" argument for an infinite that is this slow and stupid to watch. Not with the amount of knockback that DOA has, and how tight many of the stages are. If we were talking a specific area of a specific stage which could be avoided with a degree of intelligence, thats entirely different.
It is actually techable, and even moreso on the reaction time to tech since the character is static in the air from the bounce and the initial 2P Mila does. It's so much reaction time that even a casual can mash out of it once they see that wall hit, without realizing they initiated a tech. If that doesn't scream "tech now" to a player at a tourney level who doesn't tech, he/she should rethink his time investment.
The Mila player has to create a situation where she is
directly in front of the opponent whom is
directly against a wall. It won't work from a side wall knockback, a knockback not directly against a wall, or Mila not considerably close-- because the combination of her initial
2P distance, her ground tracking followup, opponent not teching after 2x reaction time, and the
opponent hugging the wall, is what creates this infinite. That's the reason why the guy who posted the video isn't showcasing this in an online match, or hell, even the CPU on normal difficulty, which would have more validity on his claim about how lethal this is. It isn't. It's extremely situational,
even to a casual.
I should point out that characters with 14 or less frames can trap the opponent between a wall in the same fashion. I was able to recreate this using Kasumi and Ayane between the corner walls in every stage that had em'. This leads me to believe this is working as intended, since it is insanely easy to tech out of.