The original article is one near and dear to me since it was the first real indication that someone else was thinking about these things in context with western art music. There are several posts that I want to comment on I'll just go from the bottom up.
Irishlostboy: Making music sound more like the environment is a great idea. Rather than be used as a standard for all in game cues I would love to see music gradually transition into more noticable and recognizable out of the ambient sounds of a level to accent tension events taking place in the game.
Dannyarmstrong: No real comment other than 100% agreeing with you. Great post!
Aurican33: I actually disagree that the adaptability is out of our reach. I will grant that certain musical styles are harder to use in adaptive music than others however I think ANY musical style can be used adaptively in games.
Let's start out with the easiest of the easy: minimalism. For those who can't immidiately place the musical style think Phillip Glass. Minimalism involves multiple ostinati (repeated patterns) and musical changes fundamentally involve adding, subtracting, and altering them. These changes can be triggered by in game events and depending on the nature of your ostinati you may not even have to bring the changes in on a barline for them to sound convincing. The static nature of purely minimalist writing would allow for more structured melodic lines to be cued in for key events and frequently accent changes in the ostinati make the same line sound quite different.
For those of you who frequent euro clubs my description of minimalism probably sounded very familiar. That's right, techno/trance music is not only wildly popular but also subject to the same additive structure as minimalism. It can be manipulated in the same ways.
Perhaps the next 'simplist' implementation is with pop/rock/funk/(shudder)country/etc. This actually isn't that simple at all compared to the above but my ultimate ideal of "Wagnerian Game Scoring" makes it look like a cakewalk (no offense to cakewalk product users out there, SONAR is great, I'm just a digidesign kinda guy). Here you have enormous creative freedom with a huge price to boot. You have to finish phrases. This means that if you need to have a contrasting event mid phrase you need to do it with dynamics, articulation, orchestration, or lyrics. It also bears mentioning that in these styles you typically have to wait for the next strong beat to have any significant change so there may be a slight delay between the event trigger and the audible cue.
Another big problem with dynamic scoring in this style is that everybody knows and expects to hear these song forms played out. What happens when a player completes the sequence before the cue runs out? What happens if they take longer than the whole cue? There are a lot of creative responses to this ranging from tempo modulation (thank goodness there's software that can do this without sounding like junk now) to the simple fade out. The cuteist solution I've found is used by Yoko Kanno in the "Run Rabbit Junk" cue found in many places throughout the Stand Alone Complex series. She just ends it with a one beat statement wherever the cue needs to end. I know, musically horrible right? Actually it's suprisingly effective because the cue itself is used to accent action and the end marks this action grinding to a halt.
There are a myriad of other musical problems but the point I'm trying to make is that all of them are ones that can be surmounted without a musical revolution.
My personal ideal of the "Wagnarian Game Score" has even more with the problems of coming up with leit motifs that can be played over each other even if offset by a few bars, not to mention having transposed versions for all of the harmonic environments they might have to be played in. Even so, while being both difficult, time consuming, and well beyond the sound budget of any game company in exsistance (actually, this may not be true. I have no idea what the rock band and guitair hero liscensing fees were but they must have been astronomical.).
The technology is there. I know this because I've been able to do all these things in protools for years. I know developers can script in game triggers because... well... they do. Synching these two is definately not beyond the industry's technical capabilities. The problems facing game music advancing in this direction have more to do with where it lies in the priorites of most companies. Heck, half of the games that win awards for their music don't even do it internally. These kind of endeavors are not the sort of thing you can outsource to Jeremey Soule because they require the compositional team to be on board and adapting at every stage of developement.
Finally the biggest barrier is that it would require having larger and more artisticly savvy sound teams and with game sound in it's present state it's a heck of a lot cheaper to produce than any other part of production. It's not all that uncommon to have only one Audio Designer/Composer/Audio Programmer on a title and then some credits for 3rd party contractors who help out with late production. Why jack up production costs for something that a mouth breathing public might not even notice? Everyone can immediately see the higher poly count or sweet volumetric effects but in one cursory playthrough how many players would even notice a well implemented adaptive score?