Usually these movies are brought straight to video/dvd to make sure everyone gets it as soon as possible(i.e. Much cheaper to skip the theatre and jump straight to video.)
A simple way to spot a Disney Sequel is the advertisement "Straight to Video" or anything Disney with a two or above on the end of it.
"Lion King 1.5?" Might as well call it "Lion King we butchered the animation, hired no-name voice actors, and added some useless side character to help the excessively deep children's story."