Campaign Defending

Hello, this is my third thread I've posted and I recently came up with this idea.

Wouldn't it be cool if you could defend in the campaign? I mean you can attack against goblins, but has anyone wanted to see your own defenses in action? This would be another fifty levels but defending against pesky little goblins and their army. You might be thinking what you would get out of this, so I came up with a scheme. If you win against their attack, you get the amount of money as in the attacking campaign, so P.E.K.K.As playhouse defending version, you would win 700000 gold and elixir if they didn't get any stars. Though defending would get harder. It would progress from barbarians to archers etc. and mixes in the end. The last level would be something like 5 level three dragons plus 20 level six archers. But in return for defending that, you would win 800000 gold and elixir. This defending plan would be next to the Attack! icon and would show you what the attacks would have, such as 50 level three barbs, 25 level four archers, 25 level five goblins and 3 level 2 balloons. This way you can see yourself defending, and get money out of it.

Thank you for reading this, and please only give constructive feedback.

Yeah it would be cool, being able to survive waves of attacks by goblins, just that I think it would be hard to implement. The cpu would have to calculate what to take out and where to place troops, so he might end up screwing the thing up xD. Apart from that I like the idea!