Designating a Target improvement

Introduction

Within the current mechanics for AFV's, DT (designated target) is a powerful active ability, which has 2 options for usage actually. The first one is the non penalty / max damage ability when you designated a target and the second one is what people might not see in the first place, the denial of gameplay for the target while the he is designated.

This comes with a prize of some risk, depending on what AFV you are using in what match up. You need ~2-3(not sure actually) seconds and a line of sight to designate a target . On paper it might seem a fairly low amount, but ingame it feels long and often enough you break the line of sight for some reason . While i agree that you need this kind of risk for a relatively powerful ability, the cooldown on it is quite long and i would like to see statistics on how much people use this ability actually per battle.

Suggestion

What i thought of an improvement aims directly on the ability cooldown itself as it should reward some of its risk and a good choice / teamwork . How i would do this ?
When you designate a target with full health, and within the designation you kill the target due good calling/ teamwork / focus fire, you should be rewarded with lower cooldown for the ability. Currently it is 1 minute. If you successfully killed a full HP designated target the cooldown for the ability should be reduced for the next usage , for lets say 30 seconds / 50% , but just for the next usage. If the next designated target is not killed within the time , you should have the regular cooldown again.

Requirements for this:

• Designated Target needs to have 80% or more HP
• The Target needs to be killed within the timeframe the ability is used on it
• Targets that have below 80% HP, should not give a ability cooldown or as another option you grant for every 5% of HP that is below 80% a 5 second cooldown increase based on the 30 seconds. 

80% +   = 30 seconds cooldown
75-79% = 35 seconds cooldown
70-74% = 40 seconds cooldown
65-69% = 45 seconds cooldown
60-64% = 50 seconds cooldown
55-59% = 55 seconds cooldown
50-54% = 60 seconds cooldown (regular cooldown)

Reasoning

It should be rewarded if you focus down a target within the timeframe, although i don't know if this might be too powerful for PvE. If that is the case, you can decrease the amount of effectiveness for this ability when used frequently in short time, within the "rewarded cooldown".