On the adjustable brightness. If you bloom it out ridiculously and take it inside a room, you can still aim it both eyes open. As above, I and everyone I know that uses a dot adjusts it twice a day- once in the morning you turn it up, as evening hits you turn it down two levels. Same as the carbine.
And I and most of the guys I know, which includes some door kickers and LE guys in my training group, prefer the auto adjust. I haven't had the trouble you've had, and it's not for lack of trying. Only time I've had an LED RMR dot wash out is when aiming directly at a bright light source (ie spotlight, headlight, etc), but that's just because the LED physically isn't bright enough on max, not because it didn't adjust. It's pretty easy for anyone with a red dot to verify this stuff for themselves, so you can all figure out what works for you.
One thing I've seen from those who've apparently read about dots but not used them - there seems to be an assumption that the RMR sights adjust brightness based on the light conditions where the shooter is. That's not been my experience; the light sensor is pointed forward like the dot, and adjusts brightness based on where it's pointed. The "dual illuminated" RMR sights are the opposite, their brightness is dependent on light over the shooter, and does not compensate for aiming into a brighter area.
We all have different perspectives on this stuff, but some of the advice I've seen here (including from Blue who came here asking for input) seems to be based on the idea that what's good for one application (like competition or special ops) is automatically good for another (like carry). I do take issue with that, and with some exceptions I think most of us here are intelligent enough to consider the differences.
A couple other points Form - you keep mentioning both eyes open. Yeah, I kind of take that for granted since I've always done that; IMO anyone serious about this stuff should be shooting with both eyes open if they can, along with practicing to aim with either eye.
About the dot blooming the window when it's too bright - that's not too much of a problem when the lens is clear, but concealed carry pistols tend to pick up lint and gunk in the window and the blooming can get a lot worse, to the point the optic is useless and in the way. IMO you're opting to deal with a much higher likelihood of that happening, while I'm opting to deal with a very small likelihood the dot won't be visible but the irons will still be available.
One final thought - for guys who do insist on setting a fixed brightness and screwing with it several times a day - that's a whole lot easier on an adjustable RMR than it is on the DPP with it's single center button.
