I completely agree. Why Wwise doesn't use a namespace is beyond me. Seems silly.
For me it was Photon that also had a global namespaced Class called "ErrorCode". So I had to make a namespace for that, and then re-integrate Wwise.
Also Wwise doesn't register that I reset my project through Unity Collaborate. I had to actually find the "InstallNotCompleted" file and delete it manually, which seems weird.