Well, here is the thing...
Disneyland at Christmas Time is much more than just decorations. It's a detailed, immersive, all-encompassing experience. You can see some awesome decorations in Disneyland itself without ever stepping foot in DCA, but it's more than that. New Orleans Square, ToonTown, Main Street, etc., all have different themes to their decor. (In fact, in the Disneyland at Christmas Time Superthread, every Monday I do a countdown to the start date of the holiday season, and I am now spotlighting a different 'area' or highlight of the DLR holiday season in photos, creating a sort of theme for the week, as we get closer to 11/14. This past week's theme has been the charmingly rustic Santa's Reindeer Round-Up, and in 2 days I will put the spotlight on a totally different area of DLR, with photos.)
There are all sorts of things to enjoy about the season at DLR. The GCH lobby, for example, is a wonderful way to relax with a snack and a beverage by the giant tree, and soak in the festive holiday spirit while listening to Christmas music provided by carolers, a pianist and a guitarist.
In Disneyland itself, along with the changing themes of the actual decorations in each land, there are also audible touches in the air, like familiar Christmas songs delivered in the style of that land, i.e., "Deck the Halls" with a jazz twist in New Orleans Square; "Jingle Bells," country-western style, in Frontierland; "Winter Wonderland" with a calypso beat in Adventureland, etc. In ToonTown you will hear a soundtrack of characters singing these songs.
The nighttime Winter Castle, IASW Holiday (at night) and the snow on Main Street cannot be missed. The lights on Main Street after dark are gorgeous.
So the question is - even though there is construction going on in DCA, and the holiday decorations in DCA will be scaled down quite a bit, can you have this overall experience by going at another time of year, like next March? Would you rather wait and return to DLR for a future holiday season, when everything is finished at DCA? Or does it sound like something you'd want to do now?
Yes, it will be crowded over Thanksgiving weekend, but does the overall experience sound worthwhile to be able to deal with it?