I think what L&P means when he says it won't affect the story by having it removed is if you don't send Dylan away Sophia would never have learnt of the twist and the Dylan path moves on, if you do send him away she leaves him at the school as punishment for the twist and removes him from the story almost all together almost the same as no twist but she leaves him there for protection instead.
I think it's your dislike of Dylan and personal head canon that won't let you accept that the twist is gone.
I don't dislike Dylan, I just find his route to be a bore. I've said time and time again that if there was an event that looked interesting enough, I'd possibly reconsider my stance on not playing it. But take Dylan's last event as an example, from what I've seen it's just a rehash of the Patricia scene in the park on PD 5. And Patricia has the advantage of being hot and hilarious.
On the Dylan route, it doesn't help that it's actually Aiden I don't like (well, blackmail in general really). But to continue the route you need to accept his tasks. And if you do send Dylan away, there's a chance of more naked Ellie. And I'd rather see boobs and pussy than dick. Plus Dylan goes to a better school on the boarding school route. One without Bennett, who is just there to sleaze on hot teachers, and because it's a job he can put no effort into.
Also, my reason for wanting to keep the Twist wasn't because it made Dylan look bad, but because I saw great potential for some real character growth, much like we're seeing with Ellie at the moment, actually having a caring relationship with Jules, as opposed to her boyfriends that she discards when they no longer serve her purpose. Yeah, Dylan might have fucked up, but a character struggling to overcome past mistakes is one of my favourite storylines. He might not actually achieve redemption per se, but it would have been great to see him try, and I would have respected him for that.
It doesn't matter if you send Dylan and Zac to boarding school or not. The Twist would be in play because it was the driving force behind the story and in the indirect cause of blackmail by Aiden. We learn of the reason behind it by taking an alternate path. This is why if you want to know the full story, you have to play all the paths and not lock out one because hints and answers are found in other parts of the path.
If you choose not to play all the paths, you're missing critical elements of the overall story.
The manner of how Dylan is acting and the conversation between Sophia and Alyssa in the cafe make absolutely no sense. I said it once, and I'll repeat it; just because you remove one piece of the story because your audience has an adverse reaction to it doesn't mean the story can carry on if you remove one part of that story. He should have gone back and reviewed the storyline after eliminating that piece of the story.
And it's that the story wasn't reworked that has me concerned that the Twist might still be in play. Now that the idea has been put into my head (thanks a fucking lot
nexer 
), I just can't shake it, as much as I'd like to.