CapnZapp
Legend
I would think it easier to simply say "don't play modules out of order if you're bothered by continuity".To each his own, but I feel the campaign is already on shaky ground by not retiring the Season One adventures prior to this point.
Most Season One adventures don't make narrative sense if run for characters who have already played an adventure from any other season -- Season Two presumes that the dragon has already attacked Phlan and many refugees have made their way to Mulmaster, while Season Three presumes that, after the Fall of Mulmaster, the Phlan refugees migrate toward the city of Hillsfar. The initial Season Four module presumes that the characters are sent by their faction representatives to investigate a threat to their plans to re-take the city.
I could understand managing to fit DDEX 01-11 to -15 into a character's log who also has played one of these other modules, but it simply doesn't make narrative sense for someone who's played, say, DDEX 02-11 Oubliette of Fort Iron to then go back and play DDEX 01-03 Shadow on the Moonsea -- not only does it present Phlan in a state that doesn't exist as of the time of DDEX 02-11, but it presents Elisande, a character the group interacts with in DDEX 02-11, as if the group had never seen her before.
Granted, a good DM can overcome some of these problems, but a good DM shouldn't have to -- the campaign should be presented in such a way that the DM can focus on telling the current story without having to be an expert on every previous season, otherwise it becomes challenging to recruit new DMs who aren't already experts in AL lore. And even more to the point, as AL moves away from the Moonsea and focuses more on adventures in the Sword Coast area, and as more and more convention developers use the Moonsea to develop their own stories, the disconnect between the old AL Moonsea adventures and the current state of both AL and the Moonsea becomes more and more difficult to reconcile.
Lastly, retiring the old adventures allows the rewards used in those adventures to be re-used in newer adventures, as a way of allowing players who didn't get to play the old adventures to still gain certain treasures that were only available in those modules. It also allows the campaign staff to effectively remove problematic treasures from the campaign by not renewing them in new modules, meaning only the oldest characters, who by now are high enough level that new players won't likely interact with them, have those difficult-to-balance-for magical items.
In short, there are lots of good reasons for the campaign to retire older adventures, and some good reasons for the oldest adventures to already be retired. A categorical opposition to adventure retirement seems to me to be a foolish position to hold.
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Pauper
You seem to assume DMs need to take every other module into account. They don't. It's perfectly alright to DM a season 1 module straight, and simply ignore any continuity issues.
You seem to assume players expect the story in AL to match their home campaigns. They don't. It's perfectly alright to assume players can handle the fact they might experience stories out of sequence.
I fully understand you might aspire to a higher storytelling and continuity standard, Pauper, but then you could simply elect to not touch older modules yourself.