I'm not sure there is much worth in imitating a Roman Emperor. They were violent megalomaniacal psychopaths to a man. There is little, about Marcus as a human being, I would consider "successful". Just because he was a good Emperor doesn't mean he was a morally successful person.
To me, successful "mind hacks" help us become more success at being better people; not enabling a horrible empire.
Of course the final word on Marcus should go to Mary Beard, the best classist of her generation:
--->“I have never understood what people get out of him. It’s a bad book. It’s hard to argue about it — it’s so evidently garbage that it’s hard to sit down with somebody who doesn’t think it’s garbage and fight it out. He’s a terrible writer."
I'm definitely not a classicist, but I think it's unfair to criticize his writing abilities too much. He wasn't writing a book for others as I understand it, it was his personal diaries. EDIT: also most people are reading a translation, so there's another layer of editorial in there.