Following features for User-Defined Auxiliary Sends would be amazing:
To understand where I'm coming from here's my "best practice", which however is more of a workaround, due to the current limitations with User-defined Aux Sends.
Looking at Attenuation Sharesets - on one hand it's great being able to design a custom curve for User-Defined Aux. But as soon as there is just one of the 4 User Aux sends that you don't to want to behave that way over distance - you're forced to set that Attenuation Aux-curve to "Use Distance volume", even though the other 3 Aux Sends might work perfectly well with that Attenuation Aux curve. So, there's really no other choice as to use individual RTPC curves for specific behaviors of the 4 Aux Sends, hance not being able to use the really nice Attenuation curve, sadly. I hope the problem comes across. From here I derive a few feature requests that would enhance the workflow drastically, while unlocking smart mixing techniques when working with User-defined Aux Sends:
1. Attenuation Sharesets could include individual curves for each of the 4 User Defined Aux Sends
... different User Aux Sends could have different "custom" curves and behave differently over distance (that alone would be awesome), plus you'd have the option to set - say one of them - to "Use Distance Volume", because it's a special one, or to "none" for not using Distance at all, just what makes most sense for each individual Aux Send. We've come across all kinds of use cases, which we couldn't solve without complex workarounds. So, that would be incredible !
2. In ActorMixer Hierarchy: Ability to "Override parent" for individual User-Defined Aux Sends
... without having to override all 4 slots. E.g. a common use case: In Actor-Mixer Hirarchy, a top parent could set global values in all 4 Aux Sends, and child containers could override just what really needs to change for that specific child. If the child object needs to override one aux slot, but not the others, that would be then easy. Right now, it's almost risky to override the parent, since you override all 4 slots. Some may use an RTPC on the parent, which then needs to be duplicated on the child, for practically no reason, except that you can only override all 4 at once. Especially in large Wwise projects is where that can cause major headache, and where the suggested would pay off I M M E N S L Y.
3. Ability to add more than 4 User-Defined Aux Sends
... e.g. in Project settings. With just 4 User-defined Aux Sends, you hit the sealing way too soon. There are many awesome and creative ways of utilizing those Aux Sends. Sometimes it's really just: "If only I had one or two more"
All of that would solve many limitations and make user defined aux sends a real weapon.