I'm not sure how I feel about a 90 hour PPL instructing me. There are already a lot of poor instructors out there that have passed the CPL and have 250 hours so when I see that a PPL with 90 hours can get an instructor rating I shake my head. Pilot DAR sums it up well in his post. Not meaning to slag the OP as I have no idea who you are and what your motivation is for teaching. However, just the regulation that states that such an inexperienced person can teach (blind leading the blind) will mean that the same type of people who eventually got 250 hours and a CPL will be able to instruct now with even less time and experience. Those are the ppl who instruct to build hours. I understand that your motivation to teach and individual personality is a huge dictator in the performance of your teaching, however, there has to be a minimum requirement for experience. Would we allow a university professor with no experience in flying, read through the books before the lesson and then teach a PPL student? Not a chance. Even though the university professor could probably do a better job than a junior instructor depending on how much time the professor put in to learning the lesson before teaching it.
I really do understand that experience isn't everything either. During my instructor rating I had to teach my instructor that he was wrong about the forces in a turn. Then I had to explain recently to him that he was wrong about slipping while on approach. The lack of understanding of slipping aerodynamics and forces in a turn of a Class 1 flight instructor is quite appalling. He tried to justify teaching that the forces in a turn are all balanced because "it's easier for some students to understand"!
Congrats for contributing to the lack of knowledge and misinformation of the majority of pilots out there. Having been an instructor for a while I really think the training program needs to be overhauled. I believe a 90 hour PPL pilot could be a great instructor but when that PPL pilot is going through the same training that got a crappy 250 hour CPL pilot to pass the flight instructor tests there is no guarantee that the PPL instructor will be good. When I started out as a flight instructor I had about 340 hours I think. I was constantly studying and as a matter of fact before I came on here I was studying a new aircraft I'm flying. It will never end! The difference between me and some "crap" instructors is that I knew I had a lack of knowledge in a lot of areas and I would always study. I had been taught just like everyone else a lot of crap that isn't true. It's just my personality that I always as "why" and want to learn about why things are. So when I was reviewing material I was taught or learning new material I would always ask why. A lot of the time I wouldn't be able to get an answer that would satisfy the why question so I would research more into it. It was either a) the instructor was correct but didn't have the knowledge to explain why, b) the instructor was wrong and didn't know how to explain it, or c) the instructor was wrong and used a flawed explanation. I've spent hours and hours going through basic theory to make sure that I understand it and to be able to explain it correctly with enough detail. I don't want to focus on myself but I want to point out that there is a lot of misinformation out there and it comes from the textbooks we use and primarily from the instructors who teach it and don't realize themselves that something is wrong.
Like I said I think everything needs to be revamped. The Flight Training Manual in Canada depicts the forces in a turn wrong so I can see why instructors would be teaching it that way, but it doesn't justify it. Someone with a high school background in physics could easily see that you can't turn if the forces are balanced. I also believe there should be an aptitude test before someone is allowed to begin flight training. The reason that's most likely not going to happen is because flight schools are all privately run and they will take anyone who will slap down some money. Eventually with some students the training pretty much has to stop but as an instructor in one case, I could see within about 3 hours that this guy can't be a pilot. Just like a DPE can judge within about 10 min if a flight test is going to go well or not. That 3 hour student couldn't give me a correct answer for 12 minus 7, I explained the definition of angle of attach to him on 5 separate occasions and with a diagram of it on the whiteboard, with everything labeled, he couldn't answer what angle of attack was. I'm not saying he couldn't complete flight training at some point in his life, but he needs to do some serious studying before he starts flight training. He is ~30 years old and I don't think he got his high school diploma.
I think a lot of experienced pilots out there would agree that the level of training and the pilots that are being turned out these days is getting lower and lower. I think it has to do with the fact that flight schools want money and students just want the license with no care about being a "good" pilot. If I could offer one bit of advice to all pilots, it would be to "be a student of aviation". If you're in it for the ladies or for the glamourous lifestyle, etc... get out! You're tainting the reputation of the real pilots! And seriously, if you can't get a girl when you're not a pilot, being a pilot really won't do much at all for you!