To further explain, Marvel and DC have a lot of AUs of their own, but there usually a case of telling a new, alternate take on a set of established characters that bring up scenarios that would be incompatible with the current continuity. Gundam doesn't have this excuse, and the prospect of alternate universes just serves as a convenient means to give writers an easy way out of writing around established lore while using old tropes in scenarios that demolish any meaning or relevance the trope's use had to the setting in the first place, and it's unforgivably lazy. I haven't given a single glance at AGE for this exact reason, and I could care less what endorsement anyone gives it; nothing about it even looks remotely interesting to me, the majority of the designs, even the versions that have yet to be cleaned for animation, are completely bland and uninspiring, and the very fact that it adds nothing to anything I'm already invested in means I have nothing to lose by just pretending it doesn't exist. That's not to say I'm a UC purist; I rather like AC a lot, in spite of it's flaws, and I'm very much enjoying the ongoing Manga retelling, and I'm sure I'd even be enjoying the Frozen Teardrop continuation, if they'd stop having a million flashbacks to silly lore-retconning things nobody cares about and actually tell the story it's supposed to be telling. The thing is, the ongoing trend of creating newer and newer alternate Universes is over-saturating the Gundam franchise with more and more crap while adding absolutely nothing of meaning to it, and if it continues, my growing lack of interest in newer Gundam works is just going to hit a peak and I'll likely stop caring about anything new at all.
To Sunrise's credit, they're animating Unicorn, and that's one of the best additions to the Gundam franchise I've had the privilege of experiencing, no matter what silly accusations people give it of being canon fanfiction or whatever /m/'s saying nowadays; at least it adds something, not to mention ties up glaring loose ends left over from CCA (which Gundam has needed for a long time now.) I think Gundam could use more of these; animated stories taking place in existing universes that build on the established setting, or at the very least tell a new story in it.
Spoiler
Yeah, I know SEED Destiny exists, but frankly, it's just the same story told over again, but exponentially worse, so I tend not to count it.
