A fair point, but I think volley is not as good as it might appear because you get it around the time you start getting several attacks a round. Spreading out your damage vs. many enemies is often not as good as focus firing multiple shots into one. I'm sure it will be useful at times but it's situational.
The beast master ranger's abilities on the other hand becomes better as he gets multiple attacks. They can now get their utility while only giving up a small amount of their own damage. It also gives better potential synergy with the hunter's own attacks. For example at the cost of a single attack a panther can pounce, knock the enemy prone while doing damage, attack again doing more damage, and then give the ranger advantage with the remainder of his own attacks. That's likely to be a substantial increase in expected damage potential compared to just attacking, even ignoring the further benefits it gives to the rest of the party.
Can you show me some math to back this assertion up? I mean, I admit I may be being dumb and missing something!
It looks like you have to be 11th level to do that, drop one of your two attacks, which are likely Prof+(STR or DEX)+Magic bonus to hit and 1d8 or higher +Prof+(STR or DEX)+Magic bonus to damage, let's lowball and say 18 stat, +1 1d8 magic weapon. So +9 to hit, 1d8+9 damage.
Panther is +7 to hit, 1d6+4 damage, causes KD, then +7 to hit, 1d6+6 damage. Let's assume AC20 for a tough single target enemy.
No-feature Ranger is thus 50% chance to hit each w/two attacks averaging 4.5+9 damage, so 13.5 DPR
Beastie is 50% chance with one, so 6.75 + 40% chance of 3.5+4 = 3 + 40% chance of 3.5+6 = 3.8 so DPR = 13.55!
0.05 gain in DPR for Beastie, w/a 40% chance of KD.
However in any situation where Volley applies, a Hunter is waaaay ahead. Also if any of his other features apply (i.e. 1d6 to damaged targets, double prof to hit large, etc.)...