How candid is too candid?

So here's my situation. I've been trying to get my foot in the door in this industry for a long time, like a looooooong time. I've switched degrees and did 5 internships, and this process has lasted over 5 years now. However, happy to say that less than 2 months from my graduation date (undergrad), I've finally secured a spot on the graduate role in equity derivatives trading at one the best banks in my city here. So sure, I'm pretty happy! Trader has been my dream job since first year of university, and it's finally starting look like a reality.

However, that's not to say I haven't hit roadblocks in my career. The biggest one came about over the last year where I didn't get a return offer from my summer analyst gig at a different bank. For those who have been in this situation, I'm sure you know how much this blows, as your final year of undergrad will now be spent busting your ass trying get something else and having a good explanation at every interview for why you didn't get a return offer from your last internship (I didn't get asked this on the interview for the job I just got, but I would consider myself lucky over anything for that). Anyways, I was a summer analyst on an equity derivatives structuring desk last summer, and I absolutely loved the job and gave it my 200% every day. However, when the time came around for my final review with my MD, he said that while my work was good, that I was too quiet and didn't communicate enough with the team (my work happened to be very independent, as most of it was project-based). He's actually not wrong; in my previous internships, I had the exact opposite problem, where me feeling compelled to open my mouth a bit too soon and a bit too often didn't work out well for me, so this time around, I decided to take a complete 180 and keep my head down and only bother them if I wouldn't be able to figure something out myself, and only to bring results to them, not problems. Clearly, I overcompensated, based on his comments. On a related note, I remember at the beginning of the summer he asked me what my dream job is, and I said to him trader. He referred to this at the end-of-summer review that my quiet demeanour would mean I could never be a good trader.

Naturally, this hurt, but once you let the tears settle, it's easier to look at things objectively and to learn from it. If anything, having had to deal with rejection much more than acceptance throughout my career has left me relatively unfazed by these types of situations by now so that I can see them with a much more objective eye. Now, here's my question: I really want to make sure I hit the ground running in my new job, and I feel that some of the comments my past MD made are probably the most useful for me because they pinpoint faults in my way: things that need to be fixed. Would it be a good or bad idea to reach out to him asking to talk in a little bit more detail about how I fucked up last summer so that I can be better aware of that coming up in my full time job? At this point, I really don't have any hard feelings towards him, so I feel like I'd be able to handle this professionally, and if anything, even though we may not ever be working together again, I want to keep my network close throughout my career, especially those working in the same asset class.