Mark Lisanti says Peggy Olsen is number 2 with a bullet:

Ever since Peggy left the firm, we all suspected that she would one day become Don Draper, but did we think the transformation would occur so rapidly and so thoroughly? It was some combination of disturbing and thrilling to see her in her new element, dominating with the ease of vintage Don. She's learned a great deal from the master: how to respond in times of client crisis to save a campaign, how to motivate worshipful underlings through fear and intimidation, and how to take copywriters hostage over the holidays (insisting all the while that they're free to go, even when everyone knows they're sleeping on their desks until they die of exhaustion or the work is done, whichever comes first). The speech with which she dressed down her flailing charges could've easily been one she stole, word for word, from her mentor:

Those are three different versions of the same idea. If you can't tell the difference between which part's the idea and which part's the execution of the idea, you're of no use to me. I know what you're doing because I've been you. You're hoping this sparks my imagination and then you can say, wow, she's a genius, or say anything because you want to go home. You're walking over the same ground. When you bring me something like this, it looks like cowardice. You can split this because you're not going home.

And then she handed them a sandwich. A nice touch, but still Draperian in its message:

"That's what the meatball sub is for."

Beautiful speech. It's amazing to see Peggy transform into Don Draper.