But you can blame the dev for revealing something so game-changing on one path but not the other. This was a huge deal that tainted the other path by burden of knowledge and if you're going to reveal something that huge, no matter how bad or good it is as a plot device, you do it on both paths at the same time in the same update.
Character growth? Ha!
That actually made me chuckle. There really can't be a way back for Dylan after he essentially made a deal with the schoolyard thug to blackmail his own mother into dressing more sexy. What mother could ever possibly forgive, let alone forget, something so terribly despicable? The extent of his interaction with Sophia after that should have been that he only comes home for Christmas and other major family events, but beyond that's he's pretty much disowned.
The twist was entirely unnecessary. It didn't "grow" Dylan's character, it ruined him. Aiden's a cocky little bastard with a power complex, that's enough for this blackmail plot to work, we didn't Dylan to be the instigator of it. Dylan can still have character growth, but it in a better way. His martial arts training, aside from giving him this ability, may also mature him as a large part of that is to learn discipline, restraint, respect, etc, so he may become better from it.
Also, Ellie's still something of a shallow, manipulative bitch, she hasn't changed that much, if at all. Even the shower scene in this update, whilst it did reveal some of her insecurities and vulnerabilities, show us how much she cares about what people think about her and how much she cares about her reputation in her social circles. We've also seen how she's been manipulating Sophia quite a lot into doing all these sexual things with her, so right now I'd say we've yet to see Ellie truly begin to change, if she even will.