imo, yes. vital for spacing, it's not like star players take all the shots, sometimes they need to create space for other players. and when playing with 2 all-star calibre players it's even more important. but aw'rite, we can agree to disagree.
it's not necessary for a big to shoot the 3...
having the ability to shoot a 15-18 foot jumper has just about the same impact space-wise (not to mention it puts them in better position to grab offensive rebounds).
and guess what? duncan has that ability.
but I'd really like to know why you think having two all-star caliber players would make spacing even more important...