I looked up what they said about the Dragonslayer passive effect and this is what Riot Wreckz said,
"This is a totally reasonable question.
Braum's passive requires a lot of ally interaction, probably the most of any ability in our game outside of thresh lantern. Braum getting Concussive Blows on an enemy is a call to action for his allies to focus fire that target, as a result the call needs to be very clear. We evaluated these things and made the decision that changing the iconography on his skin was too different from the base for allies to be expected to follow up in the way that we wanted, so instead took an approach to make changes to the base icons color that make it feel at home on the skin while still maintaining a consistent and readable shape language/symbol.
We totally think that the dragon face icon was cool, but pushing towards our game design goal of clarity we felt in this case making the gameplay oriented decision of providing a consistent symbol was the best choice for all players experiences."
I really hope they come in here and go, "Actually we realized that was a silly idea so here is the Dragonslayer symbol back guys."
Also for those unfamiliar with what it used to look like here is a picture: http://i.imgur.com/BLVGT1Z.jpg