Re: Perfection of waza
this is good old Asian learning style. Two years cleaning the soil, 2 years different kamae and tai sabaki, then 2 years ikkyo, and so on.
In fact if you want to be perfect, you will never finish the cleaning session.
It is a good attitude, not to try the third step, before you have done the first one. I think you just should trust your sensei. even if it might not be the best for you, but for the dynamic of the whole class, you can tell him your concerns and then do, what he decides. One lesson for you might be to defeat your exaggerated perfectionism.