I keep hearing the height question being brought up but when you look at the overall picture there have been many successful 6"4 shooting guards such as Byron Scott, D Wade, Eric Gordon (by the way I think Buddy is taller than Eric) met Eric and Coach Sampson when Indiana came down for a summer tournament a few years back. Ej can flat out ball inside outside threat injuries have hampered him in his pro career.
I think the size criticism is a little bit overblown. Buddy's wingspan was reportedly measured as 6'8.5" at KD's camp last summer. That's decent length for an NBA SG. With that said, it's not ideal.
Aside from differences in offensive skill sets, the problem with comparing Buddy to Wade and Gordon (I'll ignore the Byron Scott comparison, since the NBA game has radically changed so much in the 32 years since Scott was drafted that such a comp is meaningless) is that Wade and Gordon were much more explosive athletes in their respective primes (Wade before old age, Gordon before knee problems), allowing them to play bigger. For example, Wade is the only 6'4" or under NBA player in the last 30+ years to average more than one block per game for a season, and he did it six times. Buddy is a good athlete, but his athleticism isn't on Wade's level.
Buddy will be fine guarding 1s and 2s in the NBA, but defense isn't that straightforward. If you have a big-time offensive player at the 3 who's facing off against another 3 who shoulders the offensive load, you want a 2 who's capable of guarding that opposing 3 in order to spare your star 3 of carrying such a big load on both ends and to avoid foul trouble (i.e. you don't want Kevin Durant guarding LeBron James for an entire game, and vice versa). I don't think Buddy has the rare combination of length and athleticism required to take on such assignments against bigger wings. That places a bit of a ceiling on his potential value as a 3-and-D player.
Longer, more athletic wings also offer the type of defensive interchangeability that allows for more flexibility in schemes. One of the biggest factors in Golden State's defensive dominance is that they can roll out a bunch of highly capable 6'7"/6'8" defenders (Thompson, Green, Iguodala, Livingston, Barnes) and let them switch on screens without creating mismatches. If Buddy gets switched onto an NBA 5, 4, or a bigger 3, he's probably in trouble. Though there aren't many NBA teams switching as often as the Warriors do, it's a valuable option for coaches to have in the arsenal (especially in late-game situations, where it's done more frequently). Defenders also frequently get mismatched in transition (especially when there are cross-matches). As a guy with average 2-guard length and good but not elite athleticism, Buddy doesn't offer quite as much defensive versatility.
As I've said before, Buddy can be a plus defender in the NBA, but I understand why some bigger yet less accomplished college players may be more coveted as NBA prospects.
