Sure, you could, but why even that? It's about the effort it would take to make it simpler. I'd say there's likely an audience here for that suggestion.
an audience to do what, create an entire music program on the PCE?
Sorry, I don't think there is, at least not as far as I care to make. I've got games to write.
MML is *not* a composition device. It's expected that you compose this shit elsewhere first. Making a program to hear it as you go is time consuming. I know someone working on one for a different platform. It's a huge undertaking.
Compose the music elsewhere. Use a VST for approximations. Import into Squirrel and listen/fiddle til you get the sounds you want out of your ALREADY WRITTEN song.
If you can't be bothered to do that, then you probably shouldn't be making music. There are plenty of viable methods to COMPOSE songs. Koichi Sugiyama (Dragon Quest) composed the music for DQ on a piano. We, being in 2012, with fancy ass computers, are at a massive advantage over what he had to work with. There are 32 byte VSTs that can sound like the PCE.
When you use a tracker, you have to sample the sounds in from somewhere. They're not just there, waiting to be used. It's expected that you have the brains to at least grab sounds and start dicking around. This is not much different.
This is how my tutorial video is going to go
Step 1) Open fruityloops
Step 2) Slap 6 VSTs down (AKA 6 channels for the PSG)
Step 3) Compose some kind of song. The notes are what matters, really
Step 4) export to MIDI, feed through MML converter
Step 5) place into Squirrel sheet, compile, listen
Step 6) Fiddle with waveforms and envelopes til the song sounds nice.
Using a tracker goes something like
1) Open the tracker
2) f*ck around for awhile until you find samples you like
3) Punch in music and keep dicking around til you get it like you like
4) This shit doesn't work in a PCE game, so export to MIDI?
5) Put midi thru MML
6) Squirrel again
I am sure none of you are that disabled.