How the Windspeaker's change affects Alistar

The Cunning Keystone Mastery, "Windspeaker's Blessing," has been changed so that it now gives a flat amount of resistances based on level instead of increasing the resistances of allies by a percentage. This makes it less effective when healing beefy champions, but better for the wimps of League (carries).

So, does this make it better or worse for Alistar? In-lane, it does a better job of keeping the marksman alive. But now teamfights are less hilarious for you and less terrifying for the enemy team when there's 2-3 meatwalls that just can't die standing on top of them. The flat amount at higher levels is still nothing to sneeze at, but people with an armor item and MR item would still probably have gotten more from the %resistances.

Is it time to just always use Bond of Stone? Or is it now better for teams with melee assassins?