I think you have a wonderful room! In MHO, a sewing room/studio is a "working" room. Working rooms do appear cluttered because they are "working" rooms. The beautiful thing about having such a wonderful room is, "You never have to put your work away!" I remember when my daughter was a kid, I had to sew in the dining room and put everything away including my sewing machine. It was very hard to stay motivated.
Here you have the perfect room. What anyone else thinks (including me) doesn't matter. It's your room. Sometimes I feel that my sewing area is cluttered also and a day spent dusting and putting non-essentials away usually does the trick. I too have a large pegboard and, yes, it does look like a store - it is supposed to look like a store. Everything is there "in sight". If I put all of that away, I will forget I have it and buy a duplicate. I love, love, love my pegboard. I really don't have a lot of wall space because I have 3 large windows. They are great! One of my windows is covered with a piece of solid insulation and then I have a flannel piece over it for a design wall.
I too have a problem with my main sewing machine being too high. I can't change that so I take frequent breaks and watch my posture. Try to keep my chest forward to ease my back and that helps.
I really love your room. Try to change your thoughts about it and see if it doesn't look much more inviting. Remember, it's a "work" room and not your den. Enjoy!!! Just start sewing something you love and by thankful that you have such a great place to sew. Soft music, good lighting and your good to go! Good luck!