Not sure where that #31 pick is coming from, but regardless, I do agree that it may not be a great idea to add four rookies next year. There is playing time to worry about, and all those guys will be looking for an extension at the same time a couple of years down the road. OKC is a great example- they just could not find a way to keep all four youngsters and ended up losing Harden for a one year rental on Kevin Martin.
In all fairness, other than PG position, the Suns really could draft a player at each position and find them plenty of playing time. SG/SF lineup consists of Gerald Green, Archie Goodwin, PJ Tucker, and Dionte Christmas. PF/C positions are covered by Markieff Morris, Channing Frye, Miles Plumlee, and Alex Len.
Even if Dragic ends up being able to be a good shooting guard, the Suns could very well draft two swingmen and two PFs, and find playing time for them.
OKC example I used, at the end of the day, is a good problem to have, so my initial position may very well be incorrect.