I doubt I'll add anything new to the discussion, except the perspective of someone who's actually pursuing the SPL, but here goes: I think there's room for some education and discussion on BOTH sides. Instructors need to listen more, and prospective students also MUST be prepared to do the same. Here's my rationale:
1. The prospective pilot who's looking at an SPL as a cheap way to get into flying is very likely going to be disappointed. Let me start off by saying that I would be working on my PPL if I knew I'd be able to get a medical without having to negotiate an expensive and risky (from the perspective of being able to fly at all) incarnation of the special issuance process, so I'm not choosing this based on cost. And, partly because I'm in crowded airspace and also because I'd like to switch over if Congress actually pays attention to medical reform long enough to pass it, I knew going in that I'd be putting in extra hours.
That being said, basic piloting skills are NOT easy to master in an LSA. I've read the replies here from instructors who have their students passing their checkrides at 25 or 28 hours. I didn't even do my first solo until about 23-24 hours, and I came in already having passed the written test. I've been told that the CTSW I fly isn't the most stable airplane ever built, but any LSA is going to get blown around in crosswinds and feel more turbulence on a bumpy day. The pilot, therefore, will have to have even *more* sensitive stick-and-rudder discipline (and tolerance for the bumps) than the folks who learn on 172s. That takes time and patience, and if you can't come in to aviation understanding that it takes as long as it takes and for you, it might take longer for some reason you haven't experienced yet... this is NOT the hobby for you.
2. My first point is kind of a lead in for my second, and that is a prospective student pilot needs to find a CFI they feel they can trust, and then they need to actually DO that. As the customer, if you feel you're being diverted into something you don't need because the guy selling it is too locked-in to their business model, then by all means you should walk. But do take a moment to hear them out--a SPL is a huge limitation on your freedom to fly, and the cost/time savings might be negligible (or negative, if you train with a Sport CFI and hope to transition). More importantly, it's a pespective thing: you have to accept that once you're in training, you do NOT call the shots. You need to know your stuff, but you'd better be prepared to take direction and limits from your CFI. And since it's not unusual for that CFI to be way younger than the student, you really can't go into this with the attitude of "the customer is always right." I'm a big fan of reality (and, yes, I do my own research), but when it comes to flying, I trust my CFI implicitly. If you can't, don't fly with him/her.
3. I really wish more flight schools and CFIs understood the need for the SPC and why we pursue it. If you're a youngster building time toward your ATP, it's easy to hate on anything that bumps around the sky at 90kts. But for those of us who fly these, it's because we can't NOT fly... and ultimately, landing that Cub on a dirt/grass field (which is what I aspire to) can't be much less fun than flying regional jets on autopilot most of the time, and both deserve to be taken seriously.
Hope you have your cert soon, and safe flying...