Hello everybody here!
Stumbled into this blog just today: how incredibly refreshing to find other MIDI users looking for simple, straightforward MIDI editors/sequencers just as I do.
Sure enough, I also had a big love for the Atari ST (also owned a Falcon): everything was clear and solid with it. But, unbelievably, so many efforts have been wasted in order to turn a perfectly good musical system into a nightmare: innumerable software houses (many of which simply vanished after a few years) have tried to convince users into adopting their own crazy concoctions. Money, money, money...
Well, here's my 2 cents: there's been one really good sequencer/editor for the PC in the 2000's, namely Jazz++, which had many fantastic possibilities... without obliging anyone to even notice them!
It was my workhorse for years, way before the "Soundfont Era", and it's a real pity that nobody succeeded into perfecting a newer version; it does still run fine on Win$ 7 (haven't tried on Win$ 10).
Look around for Jazz++NT, the last official version; I haven't tried compiling it myself.
Another interesting (and actively maintained) program is SynthFont, which allows playing any MIDI track with a different Soundfont file. Sadly, it is rather slow and tricky as an editor...
And several years ago there was MidiSwing, a tiny JavaRunTime program which, at least, offered simple MIDIfile editing and playback with no hassle; it can still be found somewhere, but seems mostly abandoned by its original French developers.
No matter what Operating System you're using, once you have JavaRunTime installed you can run it -- I ran it under Puppy Linux without problems.
Now I'd like to test Sekaiju and Helio... Hints anyone?
All the best to everybody!