I am a little late to the conversation, but I do have a few observations that I wish to share.
To all the people saying "Greg is being rewarded with his own modpack", you could just as easily say that Greg is being exiled into his own getto of a modpack. As Greg has a total conversion vision for his mod, it makes sense to have a modpack that aligns with that vision rather than treating it just another mod to be tossed randomly into modpacks.
To everyone worrying about Greg giving FTB a bad name by throwing another hissy fit. If Greg can't get along with the mods he personally picks, that would be proof positive that GT is unusuable by anybody in any modpack. Otherwise it is he safest place to toss GT. See my next point.
To the suggestion that GT be dropped from all future modpacks. Yes, I suggested this myself, but Slow does have the best solution here. Best even for those who would like everyone to stop playing GT and leave Greg all alone in his own sandbox. Lets consider what would happen if GT was eliminated from all future modpacks. This will be the best case scenario, where Greg doesn't revoke GT from the older modpacks in retaliation. FTB users would fall into 3 camps:
1. Die hard GT fans that agree with Greg's vision. They would leave FTB for their own "modpack". Nobody else may be sorry to see them go, so I consider that no better or worse than having Unhinged in FTB
2. People who do not wish to use GT. No change there if Unhinged exists or not.
3. Casual GT fans. See everyone who has posted here saying "I am gonna install GT in Unleashed and set everything to easy mode". These are the people who like the GT toys, but not Greg's vision. Without a GT pack, the only response really is "Ok, here is how to do that" (ftb launcher does make the install easy, if not the config), or "Don't do that, we hate Greg". Second response is not really something we want to encourage in the forums, and the first pretty much returns things to full support for gregtech. Or the forum mods could censor all mention of Gregtech which would be draconian and make Greg look like a poor oppressed mod developer being bullied by the evil FTB team. Rather with Unhinged, we can point them to that as "The full GregTech vision". If they want just the toys, they can install it into Unleashed themselves, and see first hand how supportive Greg is for users who want the toys, but not the vision.
The route Slow has chosen is the high road, and makes it clear how Greg feels about how his mod is used. People can decide on their own if they agree with Greg or not.
One other note, I had pondered if there should be a disclaimer for "Add GT to the other modpacks at your risk only", but this would be a bad idea. An official FTB statement like that would mean one of two things: 1) the staff don't believe Greg when he says he won't misbehave again, but aren't going to enforce it. Or 2) crashing on startup does not actually violate the rules, and is thus ok. It should already be policy that there is no official support for adding mods to the modpacks, that should be good enough to cover the GT case.