I pretty much finished fixing Demon so current debuffs (except Judgments of the Just, the Protadin Thunderclap) are tracked. I'll package and make it available later this evening (Central European time).
I reshuffled a couple debuffs around (CoR is no longer a debuff of its own but it shares the same slot as Faerie Fire and Sting in the display).
AP Reduction, Attack Speed Reduction, Major Armor reduction, Minor Armor Reduction, Magic Damage Increase, Bleed Increase are covered, including the new Death Knight, Moonkin, Exotic Pet equivalents (I managed to test most except the pet ones). Frost Fever (DK Icy Touch effect, thx to Sparogh for pointing it out) appears as a single "F" in the attack speed reduction, bit ugly but I couldn't figure out how to improve it.
The debuff counter now goes over 40 (up to 99), it still changes colour as it approaches 40 and probably doesn't make any sense anymore due to the limit being lifted, but if anyone cares it's there and works.
A few caveats:
I didn't even try to touch or update its embedded libraries (AceAddon-2.0, AceConsole-2.0, Dewdrop-2.0 etc).
I have no idea how it behaves in non-english clients. If the original Demon worked, I probably didn't break anything.
I bumped the "Interface: 20400" to 30000 so it's no longer considered Out of Date by WoW 3.0. This is probably a really bad idea for even more reasons than I can imagine, and I could think about quite a few. In a week or so I haven't experienced any adverse effects, your mileage may vary.
If enough people care I guess I could register on wowace and put it up there. But most of what I did likely amounts to sacrilege to the real devs in there, so maybe I better not :-)
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Edit: Sorry for sneaking this in, wanted to avoid a ban-worthy triple-post
The repackaged Demon with the updates described above is available here:
Demon_-_Margot_maintenance_update.zip -- FileFactory.com - free file hosting --
I also managed to figure out how the name shortening logic works, and got Frost Fever to display as a slightly more intuitive "FrF" instead of "F" or "FF", less obscure or likely to be confused with Faerie Fire.
Any feedback is _very_ welcome, just bear in mind that I'm not an actual developer (or maybe I'm just too lazy) so can't implement any actual new feature. Unless it's a really damn good idea and I so want to have it that I end up figuring out how to make it work.