Most of our long line stuff apart from bucketing is precision stuff, a lot of it in a Canadian winter so door off not an option.
I used to fly in Scandinavia and we were used to keep the door on winter time, but after a couple of years of taking it off in the 30ºC heat (I moved to warmer latitudes), it's hard to go back.
Also, I don't think doing one precision job for a short period of time (let's say assembling a drill for an hour) or doing long distance sling work (where you can take a break from the uncomfortable position during the transits) is the same as sitting like a hunchback for up to 9 hours dodging power lines at MTOW (+the heat in the cabin)...
Maybe I'm getting old and my back/neck can't take it!
The 350 is probably one the few helis where being short is at your advantage for vertical reference work (at least with the door on).
The new crash worthy seats don't help either.