I love SISM, I don’t have an issue that it’s basically manual, I use it to constrain ranges. BTW Instruo Tanh3 is kind of the opposite for me, pushing more of the signal towards the min&max values; Klavis Flexshaper is something I might try for similar purposes.
If you’re set on CV control for attenuation and mixing, 4ms VCA Matrix may fit your needs.
For new stuff I might suggest Tiptop Z8000 as an interesting CV / sequence source. I’m likely getting one of those soon. Other items that may be interesting adds for you would include the Joranalog Morph 4 (see esp. the Divkid Video on that one!) and NonLinear Circuits stuff (particularly Chaos and/or logic modules).
Thanks for the update, looking forward to hearing what's next for you!