This is something I've wanted to do for a while and will be starting next week (as a "fun" project in between the other two more serious projects).
Read about my plans for a new MIDI sequencer here:
Nothing here yet, starting this next week, I'll post as things develop.
If there are things you are interested in always seeing in music composition tools, I'd be very interested in talking about them!
Also, placeholder twitter account: https://twitter.com/warpseq