As you already might know. Jóhann Jóhannsson, composer and long time collaborator with Denis Villeneuve is no longer attached and doing the soundtrack to Blade Runner 2049. The reason to why this is has never been answered until now.
The website Al Arabiya let’s us know that alot of things, one is that David Bowie was the original choice to have the role of Niander Wallace (now done by Jared Leto) but also the reason to why Jóhann Jóhannsson is not doing the soundtrack for Blade Runner 2049. The score is instead created by Hans Zimmer (Gladiator, Interstellar, Inception) and Benjamin Wallfisch (It, Annabelle Creation, Hidden Figures) and the reason is somewhat related to the result not sounding more like Vangelis.