I think it's perception, personal opinion. I'm kind of with "Celtics4ever" and "who" on this one.
I think Bradley has proven himself to be a top 3 on ball defender in this league. The guy is just outstanding on D. In addition, I think his percentages went way down in the playoffs because his shoulder was popping out every other quarter.
Intangibles - I just think Bradley is money. He has a nose for the ball on D and a nose for the rim on offense. He's also an inspirational player - he gets guys on his team juiced - that is a very valuable commodity to me if I'm a GM, those guys are rare. he is small for a 2, but as you're 3rd guard, a combo guy, very valuable to me.
I also, IMHO, think he's just starting to sniff his offensive game. His ball handling got a lot better this year and as that continues to improve he has the athletic ability to do whatever he wants on the court.
For me, therefore, I'd only consider trading Bradley straight for a lottery pick anywhere from 5-10 and only if I knew I could land a big man that I thought was a really sure thing.
But there's the rub, all these guys with lottery picks, after the true blue chippers, you have no idea how the kids are going to pan out until the rubber hits the road. Harrison Barnes could turn into a poor man's Danny Granger.
And to be honest with you, I think Bradley has more value than Granger. Granger does nothing at an elite level. Bradley has established game changing talent with his defense.
I'd only throw in an "one" extra pick if it was a top five pick. Otherwise, I'll just keep my two firsts where I think I can get great value anyway (Jeff Taylor, Doron Lamb, John Jenkins, Ezeli or "maybe" Fab Melo, or just try to package my two first round picks to move up to 15 and try to nab Meyers Leonard...