Yea but those ships for the most part don't have a large role in the Empire. I could still see the LAAT or an upgraded version as having a large role in the empire still. I can see them stealing some old ones from the clone wars, but if there was an upgraded version, which I'm sure there would be, it would be a little more powerful and in the empire's hands. I can also see the rebels having republic v-wings and ARC-170, but that is because the empire had more efficient ships to put in their place, the empire doesn't have that with the LAAT. They have the Sentinel for troop transport, but the LAAT is much more versatile.