I didn’t mention any ITB solutions, but there are some good ones out there.  I happen to like the point-and-curve graphics in LFOTool and its clones (some free alternatives, I believe).

One alternative that often flies under the radar:  Sugar Bytes’ Thesys.  Its Modulation Sequencer has eight lanes or Tracks; each with its own MIDI CC output, loop length, start, end and play direction.  That can get very complex, or you can keep it simple.