Should probably preface this by saying that my hopes and my expectations for this movie are two entirely different things...
For starters, I hope they flesh out Daisuke's character a bit more and finally give him some growth. There's definitely potential for some development of his own as hinted in media outside of the main series... plus in a movie involving his meeting the very first Chosen Child who no longer has his Digimon partner around, it'd make too much sense not to reflect on his own journey/career. It'd be nice to see them actually trying to make the 02 team a bit more memorable in their own way. TBQH, I'd be happy with any of Daisuke/Miyako/Takeru/Hikari getting said treatment as to me it'd give them a chance to grow out from under the shadow of Taichi's group.
That being said, I do hope that the introduction of this mysterious person plus the so-called "ancestor Digimon" leads into them diving into more of the background and history behind the Digital World. Super curious about how/when they ended up partnering in the first place, what sort of challenges/obstacles they might've faced and their adventures. Did those two fight together with Daigo and Maki's team or did they precede them? Was Homeostasis or Yggdrasil involved somehow?
In my mind, anything that helps expand the lore of Adventure is a win.
Ultimately I'm hopeful that this movie is received well enough that a bigger portion of the fandom can actually see these guys as 'their own' group instead, and that they're well-liked enough to eventually be included in the Adventure reboot. They deserve it IMO.
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My expectations OTOH are of course a lot lower. I'd be shocked if they don't end up making another movie in the vein of Kizuna. Either way I see them trying to wrap everything up with a story that doesn't really change all that much beyond the partnership time limit thing.
I do expect Daisuke to be the only 02 kid to actually grow as a character throughout the story. Given his status as the leader and heart of the younger generation, I'm not holding my breath for anybody else aside from him. I don't really expect the other 5 to get too much of the limelight, which is a shame because if there was a story focusing on Hikari for instance I would've loved to see them flesh out her personality a bit more plus, with Tailmon being there, perhaps bring some closure as to Wizardmon's ultimate fate.
Given the fact that the very first Chosen doesn't have their partner anymore, and where Kizuna ended up going with Agumon/Gabumon etc., I fully anticipate Daisuke and Veemon parting ways. A bit of a downer yet not a total shocker if you think about it.
As for other stuff like the Dark Ocean I don't even really care about that much anymore. Dagomon's call was always meant to be a one-off thing to be hinted at but never seen, while the World of Darkness itself was a plot device used to introduce the idea of other dimensions out there. Hence I'm not expecting any of these to show up. Nor do I think we'll ever see Daemon again.
So long story short - I'm keeping my expectations low here, though I'll probably still enjoy watching it just cos it's Digimon.