Here’s a fun math exercise. And you can scale to whatever number you want.
Let’s pretend you’re taking 50k damage per second.
2% of 50k is 1k. So you’re healing for 1k over 4 seconds. So every second you are being healed for 250. Two hundred and fifty healing per second.
Are you trying to tell me that 250 hps is in any way impressive or game-changing?
It may as well not even be there because no tank will notice it.
You can scale the numbers to 100k dps intake and the healing provided will be a crummy, inconsequential 500 hps.
No tank in the game is going to think “Oh man that 500 hps sure would have saved me after taking 100k dps.”