I agree with getting either one's replacement in this draft.
The Hawks would have 3 years to develop the player, if needed, before replacing the one we have now. At this point in time, I expect both will play out their contracts with the Hawks and neither would get a long extension. Miller will be 30 y/o at the end of his current contract. Rice will be 30 as well.
Miller's cap hit peaks this year at $11M and goes back down to being reasonable and affordable at $7M in 2014... and then $6M in 2015, after which he is a FA. BTW, his dead money amount for this year is $7M to don't expect Zach to be cut this year.
Otoh, Rice's cap hit this year is $9.7M, the same in 2014 and a slight increase to $10.2 in 2015, after which he too is a FA.
Superbowl XLVIII Champions... "can't keep everyone".