Nope....what am I supposed to say to my students? Hi, I know that you can get your scuba certification anywhere else in a weekend, but I want you to really know what you are doing before I dump you in 80 ft. of water in a 3 knot current. Therefore, I will require you to pay me what I'm worth for the time that I need for you to complete the minimum requirements in the water to build yourself up to diving in the area where you live or choose to dive. It's a great idea, but who is going to take the time to do it right if PADI allows for it to be done in a weekend? If I personally knew my students and wanted to do a personal favor, I would exend the class. But for the average instructor, it's never going to happen. PADI is wrong here. My personal training involved hours and hours of pool experience at depths of 20+ feet. I don't remember the actual depth, but it was the area where they did the college platform diving. I'm not saying that this is necessary, but I have encountered new divers who can barely swim. :-(
Sounds good to me as long as you advertise accordingly. Some people will go to the local dive shop and get a PADI speed cert, some will come to you to learn how to do it right. Some people get their beef fix from McDonalds, others will go to a steak house and pay a lot more for a better piece of beef. I don't see how diving instruction should be any different. No reason why you have to do three courses a week for twelve people at a time. Get your cert and then pick and choose students who want advanced training. You might even be able to offer an extra tutoring option to students who are going down the PADI conveyor belt to graduate them with stronger skills.
If diving professionally is your passion, don't limit yourself!