I would like to remind you that Sakurai don't pick the characters based on their popularity only. He kept looking for unique qualities in those characters as well. That's why it's extremely important for Sakurai to pick the characters with unique qualities so they could stand out comparing to veterans rather than cookie cutter characters.
Look at newcomers
Little Mac - He's a beast on the ground with few serious flaws which is mostly landed on recovery and aerial battles. Yeah, he is one of Western's most wanted character but he was able to provided an unique gameplay for Smash.
Wii Fit Trainer - At first, she surely look like a cookie cutter character, but now we found out about her deep breathing technique so basically she is boost character where she have to activated the move in order to power up her other attacks. Also her franchise is extremely popular everywhere along with casual players. Her franchise is 6th best selling wii game, so basically the franchise have sold over 22M.
Villager - One of most wanted characters all over the worldwide. People kept clamoring for Animal Crossing representative ever since pre-Brawl hype.
Mega Man - One of most legendary and popular third-party character despite the fact that Capcom kept mismanaged the franchise. He is one of most requested character over the worldwide.
Rosalina & Luma - Mario Galaxy and Mario Galaxy protagonist. Both games are pretty much successful, so both games have been sold over 18M. She have been gaining a lot of popularity lately. I admitted that she is one of unexpected character for me at least, along with Greninja. Look at her gameplay, she actually brought a unique moveset into this game, which is Puppetmaster which work similar to Carl from Blazblue or Any Stand from JoJo Fighting game.
Greninja - I admitted that I'm mind blown by his inclusion. We finally got a true Ninja character; at best, A NINJA FROG. Yeah, Greninja is one of most recently character that have became playable character, so I can't really defend him that much however you have to face the fact that Pokemon X/Y have been sold over 12M which is pretty impressive sales in the video game industry. Also Greninja is one of most popular pokemon in X/Y. Sometime I wonder if they were planning ahead to push Froakie and it's evolution line since we're aware of the fact that Ash had Froakie in his team. Maybe, Maybe not. About his moveset, it's pure ninja moveset which excited me since every time he acted out the moves with streak of badassness.
I wouldn't comment on rumored characters unless they becomes 100% confirmed but you have to look at aspect where they came from. They could be there due to popularities, unique movesets or mechanism, or their importance to franchise and Nintendo history. Actually, I would say Sakurai and the teams did fantastic job with characters inclusions so far.
I don't remember words to words, but Sakurai said that he felt that Smash Bros could be boring game if he had to bring all of the popular and highly demanded characters in the game. I would agreed with him fully because I can't imagine the Smash without Jigglypuff, Ice Climbers, Mr. Game and Watch, R.O.B, etc because they brought so much histories to the Smash Franchise.
I know you have been wanting Ridley to be in the game so much, but I think you shouldn't fret too much right now until we see the final roster which is like 4 or 5 months away. Basically, it's wait and see game for us to see if the rumors and leaks are real or not; and how good the roster would be. Just be patience and tough it out for 4-5 months so who know Sakurai could surprise you with playable Ridley or not.
Advice: Patience is Virtue.
Edited: I think people shouldn't take rumors and leaks 100% serious until we are so sure that they are real. It's fun to reading the rumors and leaks to see what people would trying so hard to fake the list, but at same time when it come to leaks that have potentially to be real; it's great thing to keep it in our minds so we can be prepare for the reveals.
