Im almost affraid to respond here as i might be the most vocal supporter about this feature [mouth shut]
But indeed, it's much requested, and hopefully we will have it in the end [happy][happy](so hopefully they find a way to make it possible)
Wait so if we download wwise, we could put in custom music ourselves?
I asked them in the audio Q&A but they didn't answer it. But there is a chance we might be able to.
UGC will be supported most probably. So we can probably add VFX items as well (fire sparks, water jets, etc etc).
Those generally have a sound attached to them as well. So what if we create a new VFX, without visual effect but just a sound effect?
Bad thing is we cannot select a "VFX box" ingame and add a piece of music to it, but more probable we have to create a VFX item for each theme we want in the game and that particular item can only play that theme/sound.
So i guess, if we won't have custom music as a feature in-game, this "workaround" way could still save the day maybe.