The "robot tanks" does fix the issue of why the humans have yet to see a Gamilon. Even a body of one.
However in Yamato (Farewell to Space Battleship Yamato to be specific) the Gamilons did use robot soldiers to defend their flagship against Yamato's invaders. So the robots are not entirely a new idea...just much better used this time around rather than as a dubbed in English line to avoid on screen personal deaths.
Still working out what they use the "third bridge" for in this remake. Also how it stays on when they hard land the ship into places like the Floating Continent....or Pluto.