If you are a finicky eater, I can see where it might be an issue. My mom doesn't do much beans due to her stomach issues with them so it took her a while to find a decent compromise. She is almost vegan except she does eat a couple eggs per week.
I didn't eat soy or seitan for about the first 6 months of being vegan and I personally didn't have an issue with getting enough protein. It wasn't that I didn't like them but I didn't know about tempeh and I was kind of afraid of making my own tofu for a while and I didn't know I could make my own seitan. I can tell you I've put on quite a bit of muscle being vegan and it works for me.