Just because the other tactics are weak, I disagree that decoy should be made weak too. The ideal way forward would be to make the other tactics more useful. Nerfing decoy is not the way to go.
It's not difficult to make the other tactics viable. There's a lazy way to do it: just switch back sabotage, betrayal, and protect back to one tactic slot, and they would be used a lot more. It's as lazy as the way they just made them take up two tactic slots.
By calling it a silver lining, I mean it is a small piece of food they've thrown the way of the offense minded players. I mean, for someone who's starving, for whom the repeated buffs to defenses present a dark and gloomy scene, a small piece of food thrown his way is a silver lining. Doesn't equate to a feast thrown for him, on which he's thriving too much, and it's alright to take it away from him.
Hard to cover a base with decoys and remove all traps, especially if one intends to handle the town center troops (thanks Nexon, for increasing the range), stronghold troops, mortar fire, distract swarms of defenders, and everything else. Add the complexity of cleverly placed anti-tank guns, it isn't enough. So, yes, if the anti-tank guns are not placed strategically to complicate the placement of decoys, that's lazy base design. And, yes, good placement of decoys by identifying weaknesses, trading off the handling of traps versus town center troops versus stronghold troops versus other defending troops requires careful strategizing and skill. A bunch of armored cars and/or elephant archers chew through decoys rather quickly. I've seen umpteen number of attacks that just mindlessly throw decoys around going south pretty quickly.