So, some thoughts
about the announcement:
0:30: Yes, this ancient box that has glowing neon red and blue strips on either side. Clearly primitive technology...
0:55: And you're not suspicious of that? All of the sudden there are dozens of Ditto who know what Meltan looks like? Like even if many are just imitating another Ditto they saw, that still means there has to be an originator. Either there's a wild Meltan somewhere or a really old Ditto that remembers Meltan and for some reason transformed into it. How old can a Ditto be?
0:59: Um, how do you know that? This is your first time seeing a Meltan. Also when you do see an actual one later it looks exactly as Ditto transformed into so what finer details are you talking about?
1:04: Sure Professor Oak, but where are we going to keep all that Moo Moo Milk?
1:26: Oh, and the ancient box also has a white glowing Poke Ball logo on top. Those nutty ancient civilizations with their tablet writing and electronic wiring.
2:01: So the natural habitat of Meltan, a Pokemon that eats metal, is a mountain forest? And I'm sure the moisture in the air did wonders for getting rid of that rust...
2:17: UM, THAT'S CONCERNING. They're multiplying pretty rapidly. What's causing them to multiply? Is the area Willow in full or natural underground metals that the Meltan are absorbing up? If so that's a natural disaster waiting to happen, on top of a metal eater rapidly multiplying and looking for more metal!
2:37: You know this box is sounding like it's the cousin to Pandora's Box...
And of course we gotta talk about this:
Now one thing I was going to comment on was how, for a Mythical Pokemon, sounds like Meltan is going to be VERY easy to get a lot of. Kind of defeats the point of it being a Mythical. Unless, of course, Meltan as we know it now isn't the goal. By now Meltan seems to be having a Grey Goo-thing going on.
Grey Goo is actually an end-of-the-world scenario, where self-replicating nanomachines are created and they start to break things down and build more and more of themselves until they've converted everything they could into a copy of a self-replicating nanomachine. Whenever fiction uses this scenario, often they have the nanomachines create more complicated bodies, like how Zygarde is just a batch of Cells and Cores. So, maybe they're trying to do another Zygarde: while we can use Meltan on its own, what you actually want to do is get as many as you can so that they can fuse together and eventually make Perfect Forme Meltan. Pokemon Fusion isn't unheard of, you can fuse Reshiram or Zekrom with Kyurem and you can break down a 10% and 50% Zygarde that doesn't have Power Construct.
Of course, this does raise a few concerns. First off, how would this work stat wise? Do you have one main Meltan you just have absorbing all other Meltan so its Nature, IVs, and EVs are the one calculated for? When it becomes "Perfect Form" does it stay that way now or can it revert back, and if it can revert back do you get all the Meltan you used to make it back or are they gone for good but the main Meltan can now freely change between forms? If the latter is the case, making it similar to Zygarde, then how strong is base Meltan then? It can't have that good of stats because otherwise players wouldn't want to turn them into its "Perfect Form" and lose them, you want players to use all Meltan they get to turn it into its Perfect Form. But then what's the point of making Meltan its own Pokemon, why not make it unusable like the Zygarde Cells and Cores?