I'd say that this is the best news yet for Bandana DeeLC. The shop button means that there will be an actual DLC shop for this game, likely meaning that DLC characters and/or stages will be released on a fairly regular basis. The most popular characters that didn't make it into the base game will be added as DLC so that many people will buy them. This means that characters that are relatively important and well known, but not extremely difficult to make, will have a good chance of being added, hopefully including characters with original movesets and properties, like Bandana Dee, original veterans that were cut from the game, like the Ice Climbers, Squirtle, Ivysaur, and Snake, semi-clones, like Lucas and Wolf, and the clones that were cut from Melee (Young Link, Roy, and even Pichu).
It's already been shown with amiibo that Nintendo is trying to get more money from this game, and DLC is one of the best ways to do that. Think about this: The games cost $40 and $60. Amiibo cost $13 each. It is likely that each DLC character with an original moveset would cost about $5. Clones and semi-clones would likely cost about $3. DLC stages would likely cost about $3 as well. Assume that the following characters are DLC: Mewtwo (original), Rayman (original) Bandana Dee (original), Ice Climbers (original), Snake (original), Squirtle (original), Ivysaur (original), Lucas (semi-clone), Wolf (semi-clone), Roy (clone), Young Link (clone), and Pichu (clone). That makes 7 characters with original movesets and 5 characters that are clones or semi-clones. Assume that five DLC stages are released, including Miiverse (it is difficult to determine what other stages there would be, although a Rayman stage, Metal Gear stage, and Ice Climbers stage would be included if Rayman, Snake, and Ice Climbers were to be DLC).
If one was to purchase all of the DLC characters (I would) and stages (I most likely would), assuming the characters and stages listed here, it would cost him/her $65, which is more than either one of the games. If one buys three amiibo (I assume that this is the average number that people would buy, especially since only select characters can easily be found), it would cost him/her an additional $39, which would bring the price of extra content of this game up to $104, more than both versions of Smash 4 combined. Nintendo would actually make more money from the extra content of this game (assuming a fair amount of it is bought) than from another installment in the Smash series (before DLC and extra content). Before the next game, more characters would be introduced and become popular in established Nintendo series and new ones, meaning there would not be a big problem with making the roster for the next Smash game. Therefore, Nintendo has everything to gain from this, and little, if nothing, to lose.
TL;DR Rayman gives us more hope (certainty) than ever that Bandana Dee can be added as DLC, as a shop icon is useless without a legitimate shop. Once this shop is set up, more DLC will be added in order to maintain the usefulness of the shop. DLC makes great sense from a business standpoint, as it makes people pay a fair amount of money to get extra content that Nintendo knows that people want, allowing them to profit greatly from it. The more DLC there is, the better the chance that that DLC will be DeeLC.
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