For people who had the maps (besides the 3 Mythic Maps that Microsoft was holding hostage with ODST), it felt like just more bad justification at the $60 price tag that Microsoft insisted on. However, yeah, in practice it worked great because it greatly improved Halo 3's DLC maps situation (Though don't forget that Halo 2 had the best DLC population of the entire franchise... because all the maps either launched or became free after several weeks). In contrast, CE:A shipping with only the Anniversary maps was just another dagger into Reach's multiplayer.
Only Halo 2 and Halo 3 have achieved majority DLC adoption due to how their DLC was made available. Halo 2 with the freeness, Halo 3 didn't get the majority adoption until Mythic, to the point that Bungie was able to mark almost the entirety of matchmaking as DLC-optional and you'd still regularly get DLC.
Contrast this with the Reach side of the Anniversary disc:
1) Only had the Anniversary maps
2) Could not even load the other DLC. So the disc didn't even sell DLC to the owners of it.
3) Playlists that the Anniversary disc could enter were not able to mark Reach disc maps as optional, so the Anniversary playlists could only ever have the six versus maps playable.
a) This meant that Blood Gulch, which could be considered
the Halo 1 multiplayer map, was not playable in Halo 1 mode in matchmaking. It was in Reach as part of Forge World. But since Reach disc maps couldn't be used in the Anni playlists, it was never playable in Halo 1 mode online. 343 could have easily had Halo 1 Slayer on Blood Gulch in
other playlists, but they were so insistent on putting the Halo 1 gametype behind a paywall, it never happened. Bask in the silliness.
b) This also meant none of the other Forge remakes of classic maps were playable in Halo 1 mode, because Forge World was unavailable to Annidisc users. The Bungie version of the classic playlist actually had MORE classic maps than the 343 version. So in a way, 343 flipped off their forge community and said "fuck your maps. Play only our official ones and enjoy it."
4) They ran out of room on the disc for the Anniversary gametype that lets you use the Halo 1 pistol. So you cannot even play Halo 1 mode out of the box with the Halo 1 Anniversary disc, you have to go online and find someone's fileshare to download it from. You can only save it from matchmaking if you have Gold.
5) I could go on forever about the handling of Reach and the anniversary disc.
6) It would have actually been
less harmful and more consumer friendly if they had just included only the Anniversary map code with Anniversary. At least the Anniversary playlists would have been able to use the Reach disc maps then.