In general I very much agree that randomness and pure maths aren't the best at producing musical results unless they also have some built-in music theory smarts…or can be sent on to apps/plugins that do, which is pretty easy. But I've always gotten the most immediately useful output by sticking mainly with apps that start out musical rather than math-y or random-based, then let me mess about with their output, maybe by using math-y and random options, but even more likely, if the messing about is also theory-based, as is, say, EZ-Keys, or RapidComposer, which can both send any MIDI file through any chords. Any DAW with a chord track should be as useful, but I gather that not all "chord tracks" have the same powers:)My feeling is the M31 is very complex and would take time to produce anything resembling music.
DAWS I know that are great at musical MIDI manipulations are Logic with all its MIDI FX, Live Studio with Max 4 Live, and Reason with all its RE's and use as a plugin in other DAWS. OpusModus is the best app example I know of that blends very deep pure maths and computer concepts with a totally music-oriented purpose, but it's way expensive and super complex.
I know there are other AI and math-y type music creation tools (as opposed to all the many MIDI-manipulating ones mainly featured in this thread), but as I like to stay as genre-free as possible, I'm perfectly delighted still with both RC and EZ-Keys, both of which are less $$$, as far as I know, than any other music-generating or "creation" apps, all of which that I've looked at seem VERY genre oriented. I'd say EZ-Keys is the best blend of genre and non-genre approaches for the money that I've found, since it's both a manipulator and a creator device, plus it's dead simple.
But no doubt I'm not typical in being uninterested in any particular genre (and explicitly DIS-interested in most current pop genres), so my evaluations are likely not all that relevant to many readers here.
I must say that IMO the best MIDI FX bang for the buck is any sort of device that offers per-note probability as an option. Often just dropping out a note or adding one in at odd moments can breathe an amazing amount of life into any MIDI file.
Speed and ease of interactivity also seem to me super important features for any MIDI tool to have, genre-oriented or not, so you can instantly see and fix anything your generator/manipulator is throwing out that doesn't suit, without having to re-gen or reset anything. Which is one reason DAWs are so useful in this area.
