You still have Manu, Bown (who seems to be developing a mid-range games in this late stage of his career), and Tony and the team added Mason and Hill who both have good range; I can also see Udoka getting more comfortable in the system in his second full season under Pop and in-turn developing more consistency in his jumper, especially from behind the arc.
Again, I don't see a scenario where the Suns go monstrously BIG because it makes the team slow and limited to what they can do offensively. Forget clogging the lane for Duncan, they'll clog the lane for each other and get into foul trouble in the process.