replacing him with a perfect replica
If you can replace something with a perfect replica, then the next step would be create more and more of the perfect replica. Or replace more and more people with their perfect replica. But I don't see enough of this.
Or better, just (somehow) create a perfect replica of yourself. Because it's a perfect replica of yourself, your effective growth rate will be 2^x (with x = number of replications done). You're only limited by resouces, otherwise you (and your replica) can just replicate indefinitely.
I would like to see a story with this kind of plot/power.
In conlusion: I see the current story as an ineffective use of the power.
Too bad he's didn't think better /s.