Hi everyone! I gave it some thoughts based on all your useful suggestions, and decide to drop the Salmple project for now. Instead, I’ve decided to start with 2/3 of the Moog toys and use the eurorack as an extension of it, in order to increase modulation capabilities. Later, once I’ve got a good hang of what I already have, I can start to expand the rack and add Salmple eventually.
What do you think about something like that?
I would have still one of the best and most versatile utilities (Maths), audio/cv multiplier, frequency divider, waveshaper, super effects, and super VCA (quad), mini mixer with panning, and outs.
I feel this could drastically empower the Moog(s). Notably missing filters, VCO, and LFO, but I was planning to use the ones on the synths (to start with).
Please let me know your thoughts. My inexperience is my limit. For example, I’ve added the Doepfer mixer and Intellijel OUTs, but if you can think of a module that does both better (around the same price) please let me know. Or if you see a module that won’t bring significant changes, but can wait. Any suggestion is welcome. I’d just like to keep it within the $1300 budget for euro
Once again thank you ALL. Every suggestion played an important role in my decisions, and I feel that with your help I am getting closer and closer to what is right for me 
P.S.: can’t wait to get a bunch of answers!