The thing is-they WERE going to address that in what would have been season 4 had Filmation not been sold and shut down.
Teela taking over for Mom
Clamp Champ's intro
Snout spout was moved to She Ra's world but was meant for He-Man's world. We probably would have seen Rio Blast and Extendar as well.
He-Man on the run
Teela thinking He-Man killed Adam after she just arrives as he is changing into He-Man
The eventual son of Teela and He-Man popping up way later.
This new series is an expanded version of season 4 covering some or all of those plot points.