I love BJ, but his epitaph will read: "Incredible potential, but he refused to train consistently."
Give BJ's well-documented history of surrounding himself with yes-men who can't be bothered to question his inherent laziness, I find Dolce's version much more plausible. Dolce has worked with many dozens of fighters by now, and has thus far had only 3 problematic clients: Rampage (generally lazy and gets fat in between fights), Johnny Hendricks (was injured and also gets fat in between fights), and BJ Penn. Even these three always made weight on his watch. Rampage started camp for his fight against Machida at 260, and Dolce still managed to make weight.
In my opinion, Mike Dolce is little more than a glorified nanny. He cooks all of your meals, makes sure you eat all of your vegetables, and makes you go outside and play instead of watching TV all day. Though it sounds simple, those easy steps are the difference between success and failure in weight cutting. When we pour all of our energy into training, we're more likely to fuck up and eat the wrong shit and drink too much (okay, maybe I just mean "me" when I say "we"). I believe in and try to keep to a whole-foods plant-based diet, but I god-knows-why ate pizza last week while drunk as piss. If I had a Mike Dolce making me delicious food at all hours of the day and telling me to stop drinking after my 3rd beer, I wouldn't fuck up and would probably be ripped.
And history shown that this sort of thing is exactly what BJ needs. He needs somebody to take the reins and force him to train, force him to eat right, and force him to drill technique. He trained with hard-nosed conditioning coach Marv Marinovich for the Diego Sanchez fight and he looked like a professional sodomist for the full 5 rounds. He trained with no-nonsense striking coach Jason Parillo for his fight against Nick Diaz, and his striking was beautiful from all of the slip-and-rip drills (watch that fight again; in the first round it was gorgeous technique from BJ, and then he gassed). He 'trained' with Dolce and made the lowest weight class of his life with no problems.
If BJ had surrounded himself with such quality people for his entire career, we would remember him as the best ever. He could've beaten Jens Pulver and GSP and hell, maybe even Lyoto Machida. He could've held two belts simultaneously. The only blame that falls on his trainers is that he didn't keep the right ones around.