You have to get down to Bledsoe's defense vs. Vasquez' defense for Bledsoe to look significantly better and that depends on how much you think of the PER stat as a measure of defense.
I love Vasquez, but he's a liability on D. Bledsoe is a great defender by all accounts, and that shouldn't be under-valued.
This team's weakness was defense after all.
Bledsoe is better than Vasquez at everything but passing, and he's better at things that aren't necessarily in the box score--like beating his man and getting in the lane--opening up our offense to more than just Vasquez pick-and-roll majority of the time.
...I think Vasquez AND Bledsoe would be great on this team--not both as starters, but sharing minutes next season. Bledsoe could learn from Vasquez, and this team needs guard depth desperately. Then Vasquez takes his money elsewhere, and we have our PG.
I don't know how the team really feels about Lopez. He had a very good season on a good contract, but he was on a lottery team and couldn't get significant bench minutes on the Suns last season. Major pick-and-roll D and rebounding weakness, but very good offensively.
That, as well as center free agency plans and plans for Davis will have a big impact on what we are willing to give for Bledsoe, obviously.