Im not an expert on polearm stab, and usually have no problem with it...
That said, ive seen some people stabbing stupidly fast on melee with awlpikes, and piricing even though im hugging them with my shield... hitting before I swing after ive blocked their thrust with my shield, that seems a bit OP...and the suggestion of only pircing at the right range would fix it.
Nevertheless, this would make many other polearm really bad, and most of them are well balanced as it is.
The double stab trick isn't because of the speed of the weapon, the player makes the first stab hit at maximum possible range, then charges in and does the second stab at minimum range. This gives the appearance of the weapon being much faster than it is. Just watch for this and as long as you don't get hit by the first one, you can counter the second.
Stabbing around the shield is a footwork trick, they trick you into thinking they're going to stab more to one side, then switch to the other, or sidestep and spin at the same time.
I'm afraid this suggested fix would do nothing for either of these.
Additionally I might add that aside from the longest polearms (such as glaive) 2H generally outrange polearms already due to shitty animations, so the reason you get facehugged is that you have superior range. Making them unable to facehug, and making it so that you have better range is a bit... biased.
Speaking of the pike, stabbing at facehug range is not a simple maneuver, it takes good footwork, and even then is very easy to counter as long as you don't do something very foolish. 90% of the time when I kill someone is 1v1 with the pike it's because they were either a complete newb, or felt like they were 100% safe after going past the tip, and so totally let down their guard.