a center differential has nothing to do with torque output, it helps provide more traction and smoother, tighter cornering.
in full size vehicles, drive a 4x4 pickup on pavement in 4wd and try to turn a corner, it wont turn very sharp and when you try it will bind the drivetrain up, and if you force it through it will cause a tire to slip and hop and bounce. on dirt it wont do this nearly as bad because the tires will slip on the dirt. now try the same thing in an all wheel drive vehicle that has a center diff, like a subaru, mitsubishi, etc. it drives smooth on pavement because the center diff doesnt allow the drivetrain to bind up.
the same thing happens in r/c, you just really dont notice it happening. a center diff makes turning smoother and tighter. this is also why thicker oil in the diffs is good for fast tracks with sweeping corners and you need thinner oil for a tight track. a center diff wont make you want to add more torque, you actually can end up with less forward traction under throttle with high torque because under hard throttle it can unload the front end and the front tires just spin.
again, ive never had a one way bearing in an r/c transmission fail. sure ive had my share fail in pullstarts but never a transmission. if i do build this 2 speed differential it wont be using a normal 8x12x10mm one way bearing typically found in an r/c transmission, itll be something quite a bit larger, im looking at a 14x20x16mm one way bearing used in helis.