"I don't like the extra height afforded by the 50...I'll stick with a 40 mm obj. " There is NO extra height IF the correct rings are used. But, I agree that unless your AR is a varmint or "sniper" rifle, big scopes and high "Xs" don't make a lot of sense.
Insofar as objective size goes....scopes are not all the same.
I can "see" a lot later with my NF 2.5-10x32 than some chi-com crap with a 56mm obj.
Insofar as a hunting rifle goes, there are a better choices than an AR in a semi-auto when you look at weight, power and handling.
Hardly the ideal platform for snap shots in thick cover or trying to persuade Mr Brownie he wants to die before you do.
As with "scout rifles", the "cool factor" counts for more than any real superiority.
Their assigned duty is killing people like the M14 and M-1 before them. All three do well at that, but very few ever went hunting.
Just as short, far faster on target, as light as 16" AR 10 and a lot more thump (9.3x62).
Faster on target, lighter than AR of same power (300 WinMag) and sub MOA accuracy.
In both, note low (aka fast) scope setups vs briefcase handle on any AR.