I walked out of my first instructor course after only 3 days. I thought the Instructor course instructor was laying it on too heavy and being mega critical. He wanted perfection and appeared to want to show his knowledge and our lack thereof at every opportunity. I thought it was too much like hard work and not at all what I had expected. I ended up doing the course a couple of months later with another guy, much more relaxed and easy going.
The only problem I then had was that I struggled on the Instructor test as I wasn't fully up to standard and hadn't been taught the teaching/learning elements which would have helped.
I guess what i'm trying to say is you can go the easy route if you like but in the end, a knowledgable instructor will get you through the course and you'll probably be a better instructor for it.
I look back and wonder if i'd have survived his course but who knows.
You definitely need continuity on the course and he should put you first instead of doing tests etc. Discuss this with him and see if you could change to another instructor if available for that continuity.
As for him being a 10,000hr pilot. So what? Hours aren't everything. I know a guy who was an FIC instructor with 1500hrs and he was professional, knowledgeable instructor, very accurate in the air and had a fantastic manner when instructing. Horses for courses I guess.
Good luck and enjoy the course.