I trough that when they removed the taunt skill they just removed it entirely?
I like to think of combos/abilities that do additional or huge additional hate as having like an additional hit that scales exponentially with your hate increase, at least this makes the most sense to me when it comes to guardians
for example a base of 600 hate on irritate with 15% hate increase would be 600^1.15 = 1566 hate generated. and with 20% hate increase it would be 2156 hate generated
or an example of shield slam on a guardian with 20% hate and 800 base + 750 combo damage
(5% bonus on shield slam)
(800^1.25) + (750*1.25) = 5191 total hate
but its just a wild guess