The passing is amazing. Could everyone make that hook shot back then? There's no 3 point shot and they have to dribble with there hands on top of the ball. It's a different game.
I can see his game translating to today's NBA. Granted his shot is almost a set shot but he could have easily extended his range out beyond the arc. Maybe Rondo is the closest comparison - like in the past 40 years, not just today?
Cousy always loved Rondo's game.
When people talk about whether so-and-so player could play in the modern NBA, it's always a bit silly to focus too much on changes to the game that would have dictated a different emphasis in development. If they had had the three point shot back then, then players back then would have developed using that shot. If they allowed the dribble hand to move as far to the side of the ball back then as they do now, then guards like Cousy would have been doing crossovers and off-handed dribbles.
But there's some things they did back then that some modern players might struggle with, if they didn't develop to them. Even that small amount of footage hints at the madcap pace that the Celtics played at back in those days. During the Cousy/Russell/Auerbach era of dominance, the Celtics never averaged less than 118 possessions per game and several times averaged over 130! By today's standards, that's insane! Last year, the Pelicans led the league with a Pace of just 100.5 possessions per game.
On top of that, the top players on those teams, like Cousy & Russell, typically played 36+, or even 40+ minutes per game. Man, the mileage up and down the court those guys put in was nuts! Most modern players simply don't log those kind of giant minutes and none of the ones who do come close to running up and down the court at such an extreme pace.