Hi. I got my Deluge in September and I'm about ready to share some reflections.
For starters, I love the sidechain. I think of it less in its traditional ducker role and more of an independently triggerable third envelope with precise shaping.
My favourite technique is to have the sidechain open the filters on a held note. In the example below, the kick is sent to the sidechain, along with a silent kit part sent at a lower amount. Both are sequenced probabilistically. The bass is a constant note, hidden behind closed filters, which are opened up - lots by the kick and a little by the silent trigger.
The sidechain also modifies a heap of other elements in the track, which I won't bore you with. Maybe this is all super-obvious, but it has opened up huge creative possibilities for me.
I'd be interested to hear any other examples of people using the sidechain creatively. I'd also love multiple sidechains, but I'll save that for the feature requests.