More and better Automix Features

I already found a lot of other topics on this issue, but all are closed. So here's my take on this:

I'd love to have function that allows me to use rekordbox as my library and at the same time in performance mode being able to use automix. The main issue is that for my usage (partly extreme tempo differences between tracks) I need smooth blending quite often. Spotify does this perfectly, and also MIXX has a lot of useful options (e.g. blending time - in the example below 12 s) for this. 

This helps me to focus on the playlist and the FX/EQ'ing and let the blending smoothly happen when the track is over. manually I never manage to get these long fadings so so smooth.

Here's how MIXX handles this: