The amount of WPF is highly dependant on armor (extra required for gloves and helm). You need 13 WPF per PT when naked, and with about 50 armor you need 20-21 WPF per PT.
With PT2 you wouldn't be doing much with your throwing weps besides using them to throw at people in cloth/leather (so especially kiting archers) and horses, they still won't hurt much. I would use francescas for that cuz war darts do way less damage. darts have some pierce, but you still won't be hurting armoured gusy much besides headshots or if they running at you for full speed bonus.
Axes and pierce weps (darts/javs/jarids) have different styles of fighting. Axes are fast wind up, so more usable at close range, better against horses too. If some 2h guy is backpeddling on you, you can step back, take out an axe and throw it at him, that will get him to run back to you and stop kiting (hit x to fight with axe if you don't have time to switch). You can really rip them out at 10 yard range and be fine. Much better to bring down horses too, that extra time is often difference between getting it off and not. With javelins+ you can't do that, too slow, very risky. I would recommend going to PT4 and heavy axes. Try jarids later maybe on a skip the fun char and go to PT5 if you like them a lot more.
Javs/jarids are more accurate, and have better velocity, but take longer to throw, so are really more for someone who wants sit back a bit at harass tincans at 20-30 yards. Jarids will really hurt armored people.
Anyways, throwing is great for melee, I probably get 25-30% of my kills on battle (less on siege) with it at cost of only a few % points of characters' skill potential and can bring down multiple horses per round too. Really nice when you are low HP, instead of going out to die in 1 hit you can just stay back and throw at their better players still alive or horses, and still get a couple of kills. Also with throwing you can really pump up your STR as a shielder, since you don't need to worry about being kited, something like 24-12 very viable.
As a whole, it really expands your tactical toolset, and is also really fun too. I dunno why a lot of armored meleers grab xbow instead of throwing, xbow is a sniper weapon (altho you do have shotgunning) that takes you out of fight whilst aiming/reloading, while throwing is an up close wep with no stationary reload, and gives you more tools in a fight. Throwing is a lot more compatable as a range option for a character that's still 95% skilled for melee.