You are absolutely right. A full face helmet has zero affect on your peripheral vision, I hear much better with 2" of padding, styrofoam, & kevlar slapped over each ear, head to toe leather in 95 degree weather makes me so comfortable that I find it easy to maintain superhuman like focus,
Perhaps you and I wear different types of helmet, or maybe my peripheral vision isn't as all-encompassing as yours, but I don't find that my vision is restricted by the helmet at all. In fact, there are times when I'm riding into the sun that I will tilt the helmet down slightly, to help obscure that early morning or late afternoon dazzle. I also choose to wear earplugs with my helmet, to cut down on the fatigue and hearing loss, induced by wind noise.
My jacket and pants protect me better than any sunscreen could. They reduce the amount of dehydration due to evaporation too. And should it happen to rain, I feel more comfortable when warm and dry, with my gear on.
When DH took a tumble from his dual sport last weekend, and found his ankle pinned between the side case and the ground. Thanks to a very sturdy pair of Sidi boots, he has a sore ankle rather than a fracture.
It's a wonderful world, where we all have choices about the amount of gear that we wear when riding our bikes. I respect that your choices are different to mine, but rather think that the majority of FJR forum members favor most, if not all the gear, most if not all the time.