In BB392 Deflection really isn't worth all that much.
I just tried making a fighter with maxed-out Deflection. Pumped INT, took all the feats that pump Defl. Got it well past 100. Then I had him and BB Fighter with much lower Defl engage a bunch of beetles. Both went down PDQ, and PC did not even last much longer than BB Fighter.
The main problem is that the damn things bite so hard that even Grazes through heavy armor do a significant amount of hurt. The way the attack resolution works, there's no way to get your Defl so much higher than beetle Acc that they won't be scoring a lot of Grazes at least, which means you might as well have put the points into stats and talents that give more DPS.
This is obviously not the design intention and I'm quite sure they'll adjust the numbers so there's more utility from Defl. The stat system will look a good deal different after that as well.