Drop rates are mostly OK, the problem is that there's a modified version of Juggler going on at all times that is never communicated to the player. So you rarely get ammo for your equipped weapon. For weapons with low ammo counts but that are crucial for certain enemies and mission phases, this is a big problem. I think that a 5-10% increase in kinetic weapon ammo drops would alleviate most issues with ammo. This tends to be the major weapon type for killing unshielded adds. With the Juggler variation going on, this means you will see a lot of energy weapon ammo dropping and you'll kill orange bar enemies for periodic heavy drops, but kinetic weapon ammo runs out quickly during prolonged fights with lots of red bar enemies like Psions, Dregs, Harpies, etc. Once kinetic weapon ammo dries up, this quickly dries up Energy weapon ammo, which dries up heavy ammo because you need the heavy ammo to kill shielded enemies even if they would typically be handled by lesser weapons.