Considering it’s most likely Harrison Ford came back for Episode 7 on the condition he was killed off (he wanted Han dead in 6 but Lucas was like, “no, that hurts toy sales!”, and Ford has made it clear he does not view Han as good as his other characters like Indiana Jones and Deckard), and not to mention Carrie Fisher passing away, an EU adaptation would have been a disaster.
Not to mention the EU being adapted only works if it had begun filming not long after Episode 6. It’s one thing in 2015 for 7 to bring in Ben Solo already as an adult, but it would be quite another for an EU Episode 7 to start and grown up Jaina, Jacen, Anakin, and Ben (not to mention Mara Jade, various students and teachers of the Jedi Academy, etc.) are just there, have offscreen established relationships with the OG cast, and the movie has to waste a ton of time catching us up on a ton of characters we’ve met for the first time yet have all this important stuff to elaborate on. It’s way easier to just bring in a new cast who mostly don’t have history with prior characters and thus can be developed naturally.
Plus Lucas didn’t really give a shit about the original EU. He gave them basic rules they had to follow and left them to their devices but it was obvious he would quickly retcon or erase whatever he felt like. In fact, IIRC one of the Planet of Fear books imply the Clone Wars involves the Jedi Council fighting clones of themselves which Lucas obviously ignored when he later made the prequels. There was also the Jedi Academy books where Exar Kun appears to Luke in the form of Anakin and describes his fall to the Dark Side in a way that Anakin did not do so in Episode 2 and 3, though one could chalk this up to Exar Kun not knowing exactly himself how Anakin fell and taking a gamble thst Luke himself did not either.
Anyway, I highly doubt an even semi-accurate EU adaptation would have ever worked.