Digging deep to catch some of that water that's running out the bottom of the hole you're stuck in can be a valid technique, but it's also a good way to rip up a shoulder, lose some teeth, or get launched out of the boat because of the difference in speeds between you and the fast water. Ever try to pull out of an eddy into fast current, and let the blade that's in the current side of the boat bite a tiny bit too much and have the oar yanked right down river, while you follow the handle right upriver and out of your seat?
I'm not saying never get your oar shafts wet, but that driving your shafts that deep on 99.9% of strokes is overkill, and not only doesn't help much, but is actually quite inefficient and risky.
It's also such a small amount of water that would be in the first foot of shaft past the blade that I still think the OP's got a geometry problem before he's got a water in the oar problem. What I would be worried about regarding water in the shafts is that they're going to sink in a hurry if you lose one.