First off, Hunter is really not that great.
When you compare per 36 numbers, Hunter only leads scoring by a little bit, and that's probably because he shoots more FGA/3PA.
I would say throw both away, but keep Young out of the two, if you had to, only because he's younger, left handed, and definitely has a smoother stroke/higher release point, and can definitely bulk up. I'm not convinced R.J. Molasses Hunter can seriously become more effective bulking up, he's slow as Young, and he's already twice as less heavier than Young, (185 vs 215.)
His passing has been proclaimed as useful, but all he does is make smart bounce passes on the pick and roll, which any competent passing point/shooting guard should be able to make.
Maybe, I'm far too darn critical. But I'm not convinced when people hate on Young, but don't hate on Hunter for similar reasons. Hunter is 23, and is never going to develop handles where he can blow by defenders, and put them on skates. That just isn't feasible or reasonable to expect of. But I will say his keen ability to play basketball without nervousness, and fluidity as a seasoned player or 'coaches,' son can only attribute on the hardwood floor. Young is still lacking in maturity, growth, development, but has the length, shooting stroke, ability to score, and nothing to lose at this point, except an roster spot, which I believe Ainge will give to Young over Hunter any time of the day. Hunter can be used as trade bait or trade fodder/sweetener for a 3 way team trade. GSW may be interested?