You can still buy mewtwo, no? I feel like people should always be payed for their work. Same with mods, but that is a discussion for another day. Mewtwo was created after the release of both games and those people need to be payed for their work. Asking the company to pay out of their pocket to make this character and to just give it to people, I just can't really agree or see why that would be okay.
When it comes to amiibo's, I don't think its fair to charge for it. All of the "DLC" that are unlocked by amiibos are litterally already on the disk. You are paying for things that were made during the development time of your game. A lot of these amiibo games are starting to lock off content behind of paywall. Capcom did the same thing back then and got hammered for it. EA did the same thing and got hammered for it. Why is it okay if nintendo pulls it.
Amiibo's are also being sold out very quickly, because nintendo doesn't keep them in production for very long. So let's say that you could only get lucas if you purchased the amiibo, what if you bought into the game much later down the line and the only way to get lucas is to buy the amiibo from some person off ebay for 40+ munnies. At least with capcoms on disk dlc, at least I know I can get the thing for a consistent price. Oh and with amiibos being on disk dlc, for a complete game, you are probably going to be spending an extra 20 bucks to actually have a complete game.
This is really just screwing us consumers over and while a lot of people say that they just buy it for collectors or w.e, what about the people that don't give a crap about the shoddily made plastic models. This is only catering to that demographic and it's kind of screwing over the people who just wanted the game. If they are going to do stuff like this, at least sell the content on digital as well so that we can all get it.
Last thing, if people want change, they have to stop buying the product. That's when companies will stop and get the picture. Unfortunately, they don't look at the people discussing or arguing on forums. They look at the sales and if they can get away with something that is egregious, then you bet your monkey butts that they probably will do it.