ATG's at the front line conundrum

[Steel God]

Do you not consider that to be a bit of a "gamey" tactic because they are such an easy source of VPs or, as a relative newcomer here, am I being naiive?

Personally I do not consider it gamey play to maximize one's VPs. That is the object of the game. Killing guns because they yield high VP returns is no different than killing vehicles are a preference for the same reason, or using air strikes on naval assets for the same reason. Not gamey, just using the tools you're given to put points on the board. Although the ebb and flow of battle is romantic and all that, at the end of the day it's a game not the real thing, and the winner is determined by points not possession of the battlefield, so do what you can to put every point on the board, while minimizing the ones you give up.