The clan castle is a way of having troops to fight for you during a defence, it gives you troops, and this is what the tower is suggesting to do. You can't compare a CC or the "deception tower" to any other form of defence within the game as these involve troops to aid you.
They introduced the inferno tower to mix it up, if they added a defence that fired lava on troops like a water pistol, players would think its cool and want to, UPGRADE their town hall. Which is what supercell want, and when you say attack is always Improving so defence must as well? I actually think defence is to OP and don't find a balance in a normal battle, unless using dragons or golems and mass attacking.
And thinking about this "Deception tower" idea, I still don't think it would work, with the current form of having troops fight for you, via the clan castle, it now renders this obsolete, players will not need to use their clan castle as it no longer becomes a key element in battle, and a key element to bringing players together, why join a clan if you don't need the troops, honestly that's what it comes down, you find the social side Afterwards. On top of this you need to be actively requesting troops for Cc with this you wouldn't need to.
So even after reading the arguments it's still a no.

