It only looks OP until you see the rest of the schools level 14s... yikes. You also have to remember that evokers level7 ability is currently nonfunctional
In my PHB, the evoker (and all wizards) get a tradition feature at 6th and 10th. At 7th level, wizards get access to 4th level spells, of which there are a couple nice evocations (Fire Shield and Ice Storm come to mind).
And the 6th level ability (Potent Cantrip) is not nonfunctional - as written it applies to all cantrips, even if they aren't evocations - so for example Acid Splash and Poison Spray get the benefit of the power.