I find your question valid but so general at the same time, that if one would like to answer it would take a whole book. So I'll write one thing which Wwise is lacking: positioning of large objects (sound sources like rivers etc.). Otherwise it standing quite well to current sound requirements. At the first glance seems to be not to intuitive, especially for people with typical DAW experience but it is rewarding after getting under it's skin. I'm not completely convinced to FMOD Studio interface at this point, when it comes to manage hundred or tousands of sounds.
That's my two cents.