Personally, I feel the site actually benefits from a mix of puzzle types and difficulties.
I agree that rote copying of certain common (e.g. IQ test) questions does not provide interesting puzzles, as these are more "spot the gimmick" exercises than anything else, but taken in (great) moderation these would provide a low barrier of entry to newcomers to the site who don't have the time, the skill, or the practical experience to handle the longer form puzzles the community greatly enjoys. Speaking as someone who's pretty new, I have to say that the first few puzzles I attempted to answer were ones that were fairly quickly answerable - and that gave a sense of accomplishment and success without which I might well have lost interest in the site as requiring too deep an investment to have a chance at answering even a single question.
What would be nice is if there were a few simple puzzles active that would, well, basically be left for newer participants to take a crack at. I know there may be no practical way to ensure this, but that doesn't mean it wouldn't be nice to have.
I do feel that it's not good when essentially trivial puzzles, and their answers, get upvoted sky-high while the complex puzzles that take their setters days or more to prepare, and the answers that may take as long to arrive at, get relatively little recognition. I'm not sure that's really the same issue as short-form puzzles being seen as detrimental, but it probably doesn't help.
Anyway. As a pretty recent newcomer here, I think there's benefit in having simpler puzzles around that make the new participants feel like they can wade in slowly and still feel like they've got a chance at getting somewhere - at gaining rep, at solving more basic problems and learning from more challenging ones how to step their game up to handle tougher puzzles. Cutting the simple stuff out entirely is unwise, and if the thinking is that "insta-thought" puzzles per se should be banned, I have to disagree. That net feels far too wide for the site's own good.
One final thought. If puzzle setters don't feel that short-form puzzles are interesting or rewarding to create, there won't be many. If that means that the gap can only be filled with "IQ test" type questions, I'm not sure what is the lesser of those two evils. Ideally, setters shouldn't feel that short-form puzzles are Bad™ or unrewarding, so we can have the one without the other.