It doesn’t negatively effect the music for me at all as he was the one who introduced me to them with Dayvan Cowboy. He literally looks identical to the person on the front of CH and also the person in the liner picture collage that has bushy dark hocky/70’s hair style! His name was David and my friends and I have this little gimmick where we say he “transcended” this world and entered into a permanent Boards of Canada headspace dimension and is forever contained in the Campfire Headpase haha Dayvan/David Cowboy!
My two bands Soul Slip and Kevlar are my homage to him and his psychedelic frame of existence.
I also agree with you about the older T-shirts and wish we had a larger variety of official shirt designs.