I think that's a misconception. While AL was forced to adopt HotDQ it wasn't written to work with AL and they had to jump through hoops to make it (sort of) work.If HotDQ was written primarily to work for AL play, then how well does it serve that goal?
Which just means that CR30 (even fully deserved CR30) is way too low to be a credible end of the world threat (lest alone for a full-fledged deity).Tiamat does deserve her CR 30 rating (unlike the Tarrasque), but she is still very killable, and if the 15th level PCs have even a couple of adult dragons on their side to act as meat shields/grapplers while they fill her full of arrows, even her full CR 30 form goes from "deadly threat" to "straightforward fight." To say nothing of what would happen if they have actual high-level NPCs on their side as well (Szass Tam's wizards, Harper agents).
I still hope an eventuell MotP will provide some general deity powers (like in the 1e MotP) to retroactively buff up Tiamat (did wonders for 66hp-Lolth in 1e)