I think that SRAM's first effort at wireless is pretty damn impressive and with servo and battery improvements seamingly daily, range won't really be an issue.
In fairness, it is a very small proportion of cyclists who would need the battery capacity you need ;)
You're absolutely right, although I've very seldom had to adjust di2 once past initial setup.
The bar end junction is nice but honestly it's a patch. Shimano should have gone wireless by now.
Etap is so much easier to fit and I prefer the yaw front derailleur. I admit the shifting vs da di2 isn't as quick but it's marginal imho.