Bit late to the thread I know...
slots where fine.... 1 slot will make people spam them hard... 6 jarids and a 2 hander... 9 jarids and a 2 hander/1hander, 6 jarids 1hander sheild.....
just up the ammo and damg, and all is fixed
I agree, Javs, Jarids and Spears SHOULD be 2 slot but have more ammo, this would be the easiest way to make sure hybrids don't have too much ammo, while dedicated throwers have enough.
For example if you made Javs, and Jarids 5 for 2 slots, and Spears 6 for 2 slots, that would be okay.
The problems with accuracy, damage and wpf requirement are far bigger though.