it's usable at all lvls tbh. In Div IV and III, you have trainee's with OD lvl 6-7 on the bigs. Their OD is enough for it to work. At II and BBBL lvl, you'd probably required OD 10-12 on the bigs for it to work really well. That is also the reason why most NT's nowaday's are replacing there C's by PF's. Not only are PF's harder to defend with their JS, HA and DR, but the small trade off in ID, RB and SB that you make, can be made up for by playing a succesfull 2-3 zone. And the bonus is that if your PF happens to have a decent JR, you can use him in the Princeton attack aswell.
So where as 5 seasons ago, The things deciding good teams from the less good where the teams with Passing PG's ( OD, HA DR and PA) and high attacking bigs ( high IS), Nowaday's, it's PG's with OD, HA, DR, PA, IS and preferably ID, with instead of having the C's with high IS, it's now PF's with less IS but more JS, HA and DR.
It's pretty realistic. just think of it. Dwight Howard ( Lakers C) if a big guy, but isn't very good at defending jumpshots (not great OD). Chris Bosh (PF) is much better in defending jumpshots (so better OD) and better in making jumpshots, but isn't that strong on the inside.
If you put Bosh vs Howard in a game, you'll see that Howard will dominate inside play ( in scoring defending and rebounding). Bosh will try to pull Howard away from the ring to take a jumpshot since his defense isn't very good at that...
Problem is, in BB, Bosh is gonna beat Howard 9 out of 10 times in a game. In Reality, Howard is gonna beat Bosh 9 times out of 10. The reason is simple: Howard is taller and thus makes it hard for Bosh to defend him inside. he'll try to push Howard away from the ring on attack too, to force him to pass or take a shot from futher away.
The problem with BB, is that it doesn't take the height of a player into account. Just imagen. You put a player 1 ( 221cm, IS 10, ID 10, RB 10) vs player 2 ( 198 cm, IS 13 ID 13 RB 13)r. In BB, player 2 will dominate player 1 ( assuming neutral tactics in attack and defense) both on attack and on defense. However, in reality, the difference in height makes player 1 much to strong for player 2 to apply decent defense. Give the ball to player 1 down low in the post, and he's practically walk over player 2 ( Player 2 will have to try and push player 1 away, but with such a height difference, chances are that player 1 weights more than player 2 and thus that becomes a nearly impossible task).
In BB, the players height only affects the trainingspeed. In Reality, it does much more. It would be very hard to implement the heightfactor in determinating rebounding etc. But because that is the fact, you'll see that guards with IS combined with a bunch of PF's will beat teams with normal guards and C's without secundairies. Just look at most NT's nowaday's. 5 seasons back, they had 400-500k Monster C's ( all primairies). Nowaday's, salary is much lower because you need good secundairies... You rarely see a C with more than 300k on NT's nowadays. Most of the large communities got PF's on their teams now.
As much as we like BB to be realistic, it's damn hard to replicate the real world into a Game. Imo, they've done pretty very well. But if they change the GE, they'll be improving some things at the costs of others. It's a trade off the Devs have to evaluate.
A change in the GE also gives large communities an advantage. Those communities have more players, with different builds. So they can addapt to changes much faster than mid-size or small communities.
So if you want to use the outside tactic, it's time to find what skills the bigs need for it to work well. i reckon a high Passing, JS, JR and secundairly HA and DR on the bigs would be required ( hey, that sounds like the description of a PF...) But untill someone makes a JS 14 JR 13 big and test it out, we won't know if that is what you need to make the outside tactic work...