It already is. This would just be a nerf in ARR content where it heals more than that.
I always keep a decent supply of HQ Super Potions and HQ Max Potions for when I get in synced content via roulettes and as a tank the mitigation tools are . . . lacking.
It does suck they stopped adding potions, even if they just kept the % of max HP relatively constant and increased the allowable numbers.
No second wind is a niche self sustain support ability it should stay, it's actually useful if you dont want to eat up a healer cd or gcd.
Second wind has saved my life a lot of times.
It may be the one skill that you need to be able to sustain certain things in harder content.. and it is a last resort move... believing it has no uses is irrelevant, because it has... it can mean you do full damage through a raid instead of reduced after having been revived.
It is a good move to have as a backup.
If you're not using Second Wind, you should be sent back to the Hall of the Novice. It's that simple. Sorry.