An old project I worked on back in Unity 2.6. Pretty much just wanted to see what I could do for the first time messing around with destructible objects. I would say it turned out not to bad besides the frame rate issues.
Probably wont work on it again but I put a video up so that its another item to show off in a portfolio. Let me know what you think!
Most were rigid bodies, which id say is the cause of the frame rate drop. I made it around a year ago back when id just started with Unity so if I was to re do it I would probably try to optimise it more. A little more knowledgable now than I was back then aha.
The idea is great and with the right effects and models, people would play it only for the eye-candy.
But, I doubt that at this stage the game will run at least decent on most rigs.
Should optimize the buildings (instead of making it from hundreds or rigidbodies you could apply a shattering algorithm)
Your terrain was huge, I think that also impacts the fps.