One thing you need to think about is specialized CFI's. Throughout your training you will run into CFI's that are better at teaching a certain curriculumn than others. most draw the line in terms of Instrument/primary. Dont discount the abilities of certain CFI. He may be very good at instrument but lacking at initial. If you feel he is a time builder feel free to move away from him. He may be a little gittery as well, and wants perfection, which is a trait of a good instrument CFI. Most of the students I have average a solo at approx. 13 hours. He may be a CFI that doesnt understand a solo student and may be expecting too much out of you. Discuss this with him, and maybe seek a CFI with more experience training the newbies. From personal experience, I definetely would have a hard time going back and teaching a private, dont just assume however that he is a bad instructor, just the facts, just the facts.