It's not enough to simulate the tone of a speaker using filters.
True, but I'm not trying to emulate the tone of specific speakers. Been there, done that, and I have several amps (tube and otherwise) when I want that
sound. What I want to do is go beyond existing sounds, most of which I don't particularly like. I like the sound I get with a multiband Helix more than any of my "traditional" amps.