Ernesth, I can give so many reasons why that won't happen, but I'll limit it.
1 - They are not going to add 8 characters in from the same series, even if it is the Mario series. They already have a ton, and the last thing they need is to add a buttload more. They wouldn't have 13 newcomers with 9 of them being from the same series.
2 - Even if one or two of them get in, it still is too many for the ratios between the other series. Bowser Jr. is the most likely, but Rosalina's addition basically made it to where the odds of another character from the series would be slim to none.
3 - There are better representatives for the Mario series. Bowser Jr. is a upper one, but we also have Waluigi and Toad who have appeared in the Mario series before, who would probably be more likely than any of the 8 you've mentioned.
4 - "With as many characters and newcomers as possible" does not make a better roster. It makes it more of a fangame. People may complain about Smash's character selections, but if the fans made the decisions, well...just take a look at twitch plays Pokemon, or check out the miiverse posts asking for powerpuff girls and goku as newcomers. Asking for these characters with that reasoning does not put it above some of those requests on miiverse.
1 - They are not going to add 8 characters in from the same series, even if it is the Mario series. They already have a ton, and the last thing they need is to add a buttload more. They wouldn't have 13 newcomers with 9 of them being from the same series.
2 - Even if one or two of them get in, it still is too many for the ratios between the other series. Bowser Jr. is the most likely, but Rosalina's addition basically made it to where the odds of another character from the series would be slim to none.
3 - There are better representatives for the Mario series. Bowser Jr. is a upper one, but we also have Waluigi and Toad who have appeared in the Mario series before, who would probably be more likely than any of the 8 you've mentioned.
4 - "With as many characters and newcomers as possible" does not make a better roster. It makes it more of a fangame. People may complain about Smash's character selections, but if the fans made the decisions, well...just take a look at twitch plays Pokemon, or check out the miiverse posts asking for powerpuff girls and goku as newcomers. Asking for these characters with that reasoning does not put it above some of those requests on miiverse.