Haha, I just played the demo of the airport firefighter simulator thing.
I had to laugh a lot. Such games make me very happy. But then I was sad, because I remembered, that somewhere a mother watched at the gamebox and thought "Hey, my son loves firefighter and this big trucks, he will sure love to play a simulation with them!"

Ok, I think, with some knowledge of lod and some investment into some better motioncapturing
this game would be at least playable, but not less boring.
But it has nothing to do with the engine.
I am absolutly sure you can create good games with unity. If you have the talent,
you are probably able to create good games with gs and every other engine, too.
The engine is never a mesurement for the quality of the resulting product.