I got used to it and use the 2hand stab a lot now but I don't think its OP compared to the other weapons as they all got a similar buff.
Polearms always had an "instant stab" because it seems like the wind up of the thrust is shorter than the other weapons, and you can definitely facehug stab better with a polearm than with a 2hander. Polearm thrusts still can rear horses which 2hand cannot, giving it versatility, along with all of the hoplite weapons and pikes giving them an edge over 2handers.
1hand stab is not much different than 2hand stab, gives about much of a reach bonus as the 1hand right swing (45 bonus I think) which makes 100 reach 1handers as long as great swords doing sideswings (only 25 bonus for 2hand sideswing). Having the benefit of a shield keeps them in line with 2handers.
2handers still glance without a good speed bonus and positioning, I've glanced enough in duels and battle to see the limitations of it. Its just easier to use while keeping your focus on an enemy instead of having to lolstab. Still can downblock for a relatively longer stun on the attacker than any other attack. Honestly not that great for dueling where a chamber or hiltslash will still hit quicker then an easily predictable stab.
Its fine, imo.