measurable athleticism.
Sometimes guys who require a very fast guy to cover them are not themselves too fast. I see Crawford more as that sorta guy, hopefully. (Pops was that kinda guy, too.)
One thing I really like about Crawford is his lower strength. While I wouldn't bet against him being a good defender in his career, his length & speed aren't gonna allow him to defend like a lanky, vertical guy like Trey. Trey's the sorta guy (like Richie) who has a chance to really bother bigger, taller guys. Trey has the recovery speed to handle the quick, skilled guards, too. And the bona fide fast guys (like he proved against SClara's Carlos Stewart the year before (we really had NO ONE else that could handle that guy).