It's a given: The enemy will come at us asymmetrically. It's all he can do. If we give up the weapons that won the Cold War for us, he'll come back at us from that angle again. And then it'll be all over for us. We must keep the old while adjusting to the new, imho!
You are 100% on the money. We obviously must adjust to face and defeat the current threat from insurgents and terrorists, but we dare not over-correct and abandon what brought us to the dance. As you say, our enemies will come from whichever angle they can.