Seq’s approach is **highly** innovative. It is completely different from traditional song-mode step sequencers, trackers, and arrangers, and it will really change how you think about music.
This approach is very rare. To the best of our knowledge there have been only a few hierarchical MIDI sequencers in history (one of which was by Phil Burk, a member of the MIDI 2.0 committee!). But these sequencers were largely not modular: child elements had a single parent and could not be remixed and reused by multiple parents. Seq’s hierarchy can also be parameterized in complex ways, and sequences can be bundled into macro nodes as part of still larger hierarchies.
For more information on Seq and on past sequencer history, see our academic paper presented at AudioMostly 24: https://cs.gmu.edu/~sean/papers/audiomostly24.pdf