Well, like anything it depends on your league format and what you're trying to do. Clearly this season's a major disappointment for Bogosian but, not to compare the two too closely, Jack Johnson's just starting to emerge and he's three years older. I wouldn't expect it to take that long. Different personalities and coaches. But then you get MAB and he's maddeningly in and out of the lineup (played just 2 of the last 5 games), 2-2-4 -3 in his last 10 played, and no real keeper prospects.
If it's me, keeper league, I take Bogosian in a heartbeat. Don't forget that he's only 20 years old. Half point per game or not, MAB isn't likely to get more stable, and I'll take reduced production from a #3 overall pick with high upside any day. Bogosian was the only OHL defenseman to lead his team in scoring in '08 (61 in 60... the Petes weren't exactly lighting it up), and has pretty good upside in my book. I don't know if I agree with Dobber's 60ish, but 50ish with good PIMS is realistic.
Might be worth checking out Chris Vivlamore's AJC article a couple of days ago: http://www.ajc.com/sports/atlanta-th...an-865600.html. Sounds like a couple of days in the press box did the kid some good. Just keep in mind while you're reading it that he still plays for the Thrashers (read: 0-3-3 -3 in his last 10).