I totally agree with this statement, and that is the one reason I would like a AT, well that and driving downtown...
I do alot of shuttling mountain bikes and people up the mountains in the summer time, and am worried that the AT will not have the engine braking that the MT does.
Has anyone seen that as an issue?
Not in my experience. In fact, I went down one of the steepest, scariest declines in Colorado, Red Cone Peak, in an AT equipped vehicle and I was fine.
This isn't me, I came down the hill about 5 minutes before this guy, but it shows you how steep the trail is. There is also a 1500' drop off on either side. Incidentally, this Scout has an AT as well.
I think engine braking is one of those "nice to have" features but as long as you are aware of your vehicle's abilities and limitations, it's not neccessary. After all, this isn't the old days of drum brakes when you really needed to use your engine braking to get down a steep slope. Most vehicles have either 2 or 4 disc brakes that aren't nearly as prone to fading or overheating, at least not if they are used with a little common sense.