Having taught multiple things, among them English as a foreign language and even dance for multiple years I have just one thing to say. In virtually every lesson a student has complained about my teaching method and equivalent or higher amount said it was amazing/awesome. You can never make everyone happy. And students don't really know what they need, only what they think they want. As an example:What is good for you could be different than what is good for me. How people learn personally will differ. Some are visual learners and others are mechanical learners. Some do better with big pictures and dri down from there. Others like the details build up from details. I guess nothing I am saying is new anyone.
Good teaching in a group class will differ from private one on one lesson. Good instructors have to have an ability to read the room and adjust accordingly. Students both the slow learners and the fast learners have to feel at the end of the lesson that they got value or learned something useful. A good instructor will encourage students to go explore learning from others and also point out that sometimes they will hear contradictory things. It is good to give a quick (less than a minute) introduction to different styles of salsa dancing and explain which particular one is beging taught (for the first timers). There are many things I could write and give examples to back up. But it will take a book.
If I have to say in one line, a good teaching gives you both want you want but more importantly also what you need at right time and in right amount. A beginner is seldom in position to know or realise what they need. More importantly instructor takes effort to study and be knowledgeable about the dance. Rather than spewing out incorrect information.
My dance journey passed across many teachers to achieve my ultimate state of stagnant mediocrity. I learned a lot from each of them, including what not to do, and different dance styles also help with frame, connection, stepping, musicality etc. Just off the top of my head:
Kizomba's slow pace allows you to drill down into expressing the music, and focus on frame helped me distance myself from being a"hand leader" a bit. And allow myself to break out of rote 123 567 or 235 671 dancing on autopilot.
Sensual "Bachata" helped me by improving my body movement and improv for the start of songs.
Casino helped my linear dancing because I had decent leading skills before I began to learn linear, which is a harder dance to master.
Chachacha on2 helped me hammer down my on2 timing, I still dislike dancing chacha but my timing is pretty good.
Merengue helped me improve my stepping in Authentic Bachata, I dislike dancing Merengue but I can move my hips fairly well.
Line dancing helped me overcome my shyness about doing shines and rumba, I still suck at them and am self conscious but I do them when the music calls for it, and I absorbed the fact that you have to do them whole-heartedly to make it look at least somewhat good.
Dancing by myself helped me hammer down first timings and then body movement, footwork, and musicality.