Circle: Horrible Range, No stun, bad AP gain, easily destroyed by the slightest touch.
Up Circle: Anti Gravity. What does this accomplish? It doesnt chain to any of Jak's other moves well, certainly not his first special.
Long start up time for how useless it really is
Up Triangle: Jak's only real stun move, and it only hits in the air, where he cannot do much.
Triangle: Crap AP gain, doesnt even do a whole lot. Infact the knockback on this is so bad you cant even keep enemies in it.
Down Triangle: This has pretty much no range at all. Im serious, try jumping and using it. It wont even make it to the ground.
First Special: This has almost no range at all, you really have to plan in order to get a kill with this.
Second Special: Its okayyy. but for a lv 2 special its very delayed, I dont get why you cant stay transformed as Dark Jak and get kills that way either. You know, like that op raiden's 2nd special
Honestly, whenever I try to play jack, I find myself only using his airal forward melee, down circle, or foward Triangle to attack.
Everything else on him is just bleh.
You need some imagination, especially if you're sticking to air forward+square, down+circle and forward+triangle.
The Gyro buster isn't meant to gain much AP or stay around very long. It's just an addition on whatever else he's doing (otherwise it would last longer than 4 seconds).
The Peace Maker is one of his best attacks. Used in conjunction with his ground Beam Reflexor, he has everything he needs for anti-air. The air Beam Reflexor is hardly his only option for attacking from the air: try the Arc Wieldier (neutral triangle) or Needle Laser (forward+circle) sometime.
I agree he could probably use some slight AP-buffs: nearly every move you mentioned nets about 5 AP at the most. But the moves themselves are fine if you know when to use them.
I like to make PSASBR move-sets. Here's a few:
Never say I don't contribute: I'm The Idea Man.
Honestly his Gyro Buster drone (circle) should stay out a bit longer and go further, but the ap gain is fine. His Arc Wielder (triangle) needs a slight ap boost the distance is good. His Peace Maker (up Triangle) should get a small ap gain besides that its fine its a small stun that you can follow up if you quick. The Mass Inverter (up circle) should get a small ap boost and the effect should last a bit longer. I would be fine if this could combo to his level 1 as well as I think Jak needs it. His Needle Lazer (forward circle) needs a slight ap boost and should go a tad bit further. Other than that this move is ok it can juggle people and at the right distance help set up some other moves. It's not that his weapons are bad they just feel like they gain a very small amount ap. If they make a few changes he will be a character with a great moveset.
1/6/2013 - Defeated the #1 player in the World in a Ranked Match.
Currently maining: Parappa
Future mains: Zeus, Issac