Well, you can simply follow how those PoS network works if you're lazy. Just fork the network and switch to PoS and then you're good to go. But as mentioned above, the actual reasons are not because of technical difficulties, but more of security, decentralization, and other principal issues.

How did you arrive at this conclusion? Even if that's true, do you think those extra mining power to protect the network not worth the "extra steps" you mentioned above?