I am looking at buying a System 7 carbon to replace my trusty but knackered system 6. I was wondering about the integrated helmet comms but after reading about your issues I think I shall remain with my Sena 20S as it is totally reliable, works with in-ear monitors, can be charged when in use and the jog dial or double tap are intuitive. Just a shame it sticks out like a carbunkle.
Go and buy a Shoei Neotec 2, sell your Sena 20S and buy the SRL version which was designed to fit in recesses in the Neotec 2 so all you have outside the helmet shell are the buttons.
For long days on the bike a small battery booster pack in my top pocket and a cable to the charging point under the back of the helmet means it’s job done. I’d forget I’d plugged it in to the bike and damage the plugs when I got off if I charged from the bike