User blog comment:Attheendoftheday/Summoner Spell: Barrier Buff?/@comment-24036535-20140805220654

I think you have an interesting idea, my personal idea was more like this:

Barrier, grants a shield of X amount (Lower than heal) and Y armor and magic resist, this makes it more effective for champions with low health pools or who don't get resistances, such as ADCs and mages.

Heal, grants X+ health, increased by 1% for every 1% missing health, and grants a moderate MS  buff for one second (30-50%)

This way, Heal remains viable, and becomes more useful on tanky champons who already have resistances, who can utilise heal, Mundo and Zac come to mind, amoung other tanks in a hard matchup. While Barrier is for squishier targets, or against teams centered around burst, where Heal would be infinitely more useful against more consistant damage team comps.