Good point about getting a significant amount of health on every kill. That may prove to be more advantageous than simply activating health regeneration on kill like it does currently. Think about it: you get a portion of your total health immediately and don't have to wait for it to regenerate over time. That may allow one to go on a longer kill streak since each kill gives health which may allow one to get to full health in only a few kills. Therefore, in that respect it may turn out to be a buff rather than a nerf. The only downside is the shield only regenerates over time but that may not prove to be a significant disadvantage.