Technically Magic was a 6'9" point guard who couldn't shoot but could handle the ball like a mofo and had incredible court vision, regardless of him being 6'9".
Brad Stevens said it best. Today's game is 3 positions, not 5.
1. A ball handler
2. A post defender
3. Scorers
Archie, as TMP pointed out plays a pack line defense and as I pointed out wants to score first in transition (then he uses a motion if there is no transition opportunity).
That basically makes that post defender in his eyes a big, power forward in the traditional sense.
So basically he has a primary ball hander and a bunch of forwards/wings.
It's not positionless...but instead of five strictly defined spots (pg, sg, sf, pf, c) it's at the most 3 (pg, scoring forward, post). Under Archie it's probably two (pg, an array of forwards).