DBZ nostalgiatards are embarrassing, I remember episodes in the frieza vs goku arc being half flashbacks, background shots and ATATATATATATATATA.
However, the frieza vs goku fight had length. It was more than 10 episodes. The Jiren vs Goku fight will only be 2 episodes, and that's where Super is wrong. Dbz had bloated fights but that's preferrable to having them rushed.
If this episode was the first part in a 5-6 episode fight I wouldn't mind the reused animation. Actually I would love the episode because excluding that part everything was done about right. But this was half the fight. Unless the next episode is the best in DB history, I doubt how this fight can be salvaged.