Great to get some news on the Mega Dimension DLC!
It releases on December 10th. I think that's a great date because it is quite soon after the main game, but not too soon, which gives slow players like myself some extra time to continue with the base game. I think I should be able to complete everything I have planned in the post-game before the Mega Dimension drops. The question is whether I should make a new team for the DLC, or keep going with my in-game teams? Since the levels seem to be very high in the DLC, I think the best approach would be keep my current teams and to train them to higher levels. Maybe Hyper Train them and make sure they are properly EV-trained as well.
Chimecho and Baxcalibur are great choices for new Megas. Chimecho because it is a very unloved and unpopular Pokémon that needs a buff and more attention, Baxcalibur because it is from Gen 9. This means that there is now at least one Mega from every generation!
Cool to see some other Pokémon return as well. Corviknight, Mr. Mime, Marowak, Golisopod, Golurk, Mursharna... and more. Really nice. I hope the DLC will add at least 70 new (old) Pokémon in total, so the full number in the game goes up to at least 300.
Being able to go over level 100... now that's something I never expected to see in Pokémon. I have always liked how the max level in Pokémon is 100 instead of 99 or some other odd/"incomplete" number, but I have never once thought about the possibility of going higher than 100. This will be cool.
Diancie Event, not bad at all. I have been wondering how they would handle the Kalos mythicals, this answers the question for one of them. I'm expecting Hoopa and Volcanion to be available later on as well, either as standalone events or in the DLC. Maybe Hoopa will be catchable in the DLC since it seems that it will play a big role there. Either way, I will be sure to get the Diancie through the event, and maybe use it on a new team as well. I have never used Diancie before, so this is a good opportunity.
Who is Ansha? I guess we'll get the answer eventually. As others have noted, she bears some resemblance to Diantha.
I love how Korrina is back. She was one of the more memorable characters from X/Y and I'm happy to see her again.
Otherworldly Lumiose makes me think of the Dark Worlds in Zelda and Metroid, and the alternate universes in the Persona series. I hope it will be good, the trailers certainly give me the that impression.
Overall, this new info made me really hyped for the Mega Dimension DLC! I'm definitely getting it once it is out.