As far as Idea Weenie's variable array goes, it's a good idea, but it would probably be fairly heavy and/or bulky, as including the necessary lenses, power supplies, pulse timers, as well as the equipment to change configurations would require some complex design. The cost would be astronomical too, but it would make a good prototype for a campaigh objective.
For a ground-based installation where weight is basically not a factor it might be a good idea, but the cost would probably be so high that it would be cheaper to just buy all of the other lasers and the requisite heat sinks.
Oh, and that range is due to dispersion, after which the laser can't do any meaningful damage. It might scratch the paint, but you wouldn't be able to do much in the way of actually ablating the armour, wheras a ballistic autocannon shell will just keep going until it hits a unit or the ground, and when it does, it will deal its full damage (I assume that standard AC munitions deliver most of their damage through explosive force rather than kinetic energy).
No lenses. It is an array of small photon emitters, similar to the SPY radar. The computer changes the orders for the laser elements on an as-needed basis. Power supply would be the same fusion plant, and needing the same power as a current ER Medium.
The real fun is since it is composed of multiple smaller elements, you would have two parts of it. The control computer, and the array of elements. The Control computer is a one-crit knockout, while the subordinate elements could get hit and the rest of the system keeps on functioning (but at lower capability).
Link to it
here.
