I don't really know who you've been talking to but the vast majority of SCH players miss its DoTs, its Shadowflare, its Virus, its Eye for an Eye, its faerie's identities. There are plenty of people who are willing to still play the job, but of those of whom the conversation came about in regards to old SCH, all of them from my experience unanimously agree that it was better when it had more DoTs. And then there's the forum discussions that have popped up multiple times about SCH and wanting its DoTs back. The only players I know to dislike DoTs are now you and like 2 other people on the forums. You seem to be in the minority on that one. One thing I want to send back to you though... You ask why is it only acceptable to take from the old SCH tools, I want to ask again what makes them not work with the current SCH? I don't think you've yet to explain how those old mechanics would disrupt their current gameplay.
Perhaps this wasn't the intention, but the part of the post I saw as sass was you suggesting I look in the mirror, which comes across as very "have you looked in a mirror lately?"
I assume you don't like old SCH because you seem to have a distain for its core identity. I'm also not sure what about new SCH you like better because the only thing that's changed about SCH's gameplay has been the gutting of its DPS and the removal of Selene. SCH has gotten new buttons, yes, but those newer forms of utility did not have an impact on SCH's gameplay flow. They're not changing how you think about your GCD and what you do with it, like what those gutted DPS buttons did, or on a non-DPS related instance, Recitation and Deployment Tactics. Those are tools that actively changed how SCH thinks and handles its flow. Expedient is great, but it doesn't do that. That's not a bad thing. Not all tools are supposed to have a direct effect on gameplay, but SCH hasn't received anything that has developed its gameplay, but has had lots of things that did taken away from it.