I'd argue that was always the Destiny plan to be a constantly shifting MMO and Destiny 1 is the real outlier at this point. The teething pains right now "twisting 2 into something it wasn't" seem to be more somewhere between "twisting 2 into what it was always meant to be" and "Bungie is still learning how to run and build an MMO the hard way by ignoring most of what worked for decades" (for instance, relying so much on streaming from the disc/hard drive over streaming from the server making it real hard for them to keep all zones active at the same time because they run against disc/hard drive size limits; that's Ancient MMO Trade-Offs 101 that Bungie seems dead set on doing the weirdest possible solutions, though to Bungie's credit they aren't the only ones in this current "live service" games era learning this old lesson the hard way as games like Fallout 76 and Sea of Thieves seem just as likely to hit the exact same wall if they try to expand much more).