I prefer when my students all carry on my technical skills, but they will carry over what they work on. I've had students who have absorbed my material like a sponge. They worked hard, practiced, took lots of private lessons, and and put aside their ego and/or insecurities and actually learned what I had to teach. A number of them are champion dancers or good teachers in their own right now.
I've also had students who had no dedication, those that were lazy, those that were fearful and or resistant to my teachings, though if you were to ask them they would say they fit in the former group.
The truth is the only judge of how good a school or teacher is, is what they do in a class. The students really aren't a good judge for the most part. Some students come away being excellent, not because of the teacher but because of their own work ethic and ability to explore on their own. Their ability to take responsibility for their own learning.
Take some time if you want to become good, take lessons from different instructors, or visit numerous classes and find a teacher whose words make sense, one who uses drills that will help enforce the wwords, and if you really want to get good, look for the teacher that is kind of an [beep!], because if you really want to get good, you want someone who holds you responsible for your learning, won't let you take short cuts or give up. Someone who pushes you and challenges. A disciplinarian when necessary.
Now this isn't someone who abuses their students, but someone who is real and upfront. If you want your ego massaged you don't really want to be good, you want to feel good, a very worthwhile goal, but not the same. A firm teacher, one who won't blow sunshine up your keister, but one who can joke, is self deprecating as mush as they are critical of your own dancing.
Its a fine line, but you should be able to walk away from a lesson at times feeling happy at your progress and dancing and other times to feel slightly overwhelmed, and frustrated because they want more from you and you aren't there yet.