Hopefully the renoise team will add brackets and math rules to the sampler modulation.
It would be also very useful, if there where at least 2 independant slots/lines of filters. For example simply two buttons “1” and “2” on target boxes “filter” and “resonance”. Of course the matrix would have two additional columns.
Two filter slots are the common standard in tone generation. They can be usually switched in serial or parallel wiring. In fact I don’t even remember one synth, that has only one filter.