What improvements have you seen in hardware that have made it easier to install, operate and maintain displays in outdoor locations?”
There are a few improvements, namely, heavier, stronger case materials along with recessed and watertight sealed connector compartments. This makes mounting outdoors easier, and tougher screens are less prone to scratching. More robust circuitry for handling varying temperatures and greater power tolerances add more reliability when steady voltage isn’t available.
Although not directly related to mounting and maintenance, the fact that screen brightness is two-to-three times higher these days is what makes all the difference in the first place.