The diminishing of haste effects must go, if you already have a haste buff, like 10% or any, and you receive a new one, the duration of the next haste buff is less than a second, for an example if you have a 50% speed boost for 3 seconds after finishing a node, while already having a slight speed, or any, that 50% have no effect. Also the haste needs to be longer, much more.
There is a lot of things that has no point of using because of this, for an example, when causing a critical hit, gain 30% speed boost, after the animation is finished with the attack, the effect is already gone. There is many things like this in the game.
Remove diminishing effect of haste and increase the duration by at least twice as much.
As a programmer myself, I know this is an easy fix.