Personally, the one issue I'd have with giving blunt weapons 1/2h armor bypass is that it makes all basic light AND medium armor completely useless. That's pretty powerful right there.
As for the bonus damage for piercing weapons, I meant that to replace the +1k0, rather than be in addition to, since we were discussing making the weapon type bonuses situational. My reference to sneak attacks was that it seemed appropriate to me that the bonus given to piercing weapons should synergize with sneak attacking (though it would still be useful in other situations), rather than that sneak attack needs a buff.
Also, just FYI, the sneak attack would be a |Melee| Wisdom roll (of 6k5 for a maxed starting character) against the enemy's passive defense (which takes a -2k2 penalty), adding 1/4h to the damage increment if you're using a weapon that keys to Wisdom normally (which you probably are; that'd be a 1/2h increment for daggers, or 3/4h if you have assassin's training) and dealing double damage. Which...is a lot, but keep in mind that it's pretty situational and requires, at minimum, one action to set up (and that requires you to have the Flash Bomb Vanish tech, and a deku nut or flash bomb on hand to use for it). If you can't use the Flash Bomb Vanish tech, it's more likely to take 2 actions to set up (one to run to a hiding spot, then one to move out from hiding into range), and may be flatly impossible if there isn't sufficient cover.
If we do think it needs a nerf, I'd say drop the penalty to defense for being caught by surprise from -2k2 to -1k1, and maybe restrict the bonus to damage increment to light Wisdom weapons, rather than Wisdom weapons in general. At any rate, when you're already dishing out that kind of damage, adding 1/4h to the total amount as a function of your weapon is fairly negligible.