Here’s my philosophy regarding Smash Bros. I don’t know why I’m posting this, but whatever — it’ll help explain why I’m so easily impressed (or “pessimistic,” as someone has described me).
Apart from the really major character-based IPs like Mario and Pokémon, so long as a series has one playable representative, I have no room to complain. Metroid is all about isolation and exploration; there just aren’t a ton of fun, important, well-developed Metroid characters that lend themselves to a crossover fighting game apart from Samus. Similarly, despite being one of Nintendo’s most popular and best-selling series, Villager sufficiently represents Animal Crossing.
Given its middle position on the Nintendo totem pole and lack of adequate characters, Metroid feels complete to me with Samus and Zero Suit Samus as its playable representatives. I don’t fault Sakurai for excluding Ridley.
The counter-approach is, “well, if that series has X amount of playable characters, then so should this series!” I strongly dislike this line of thinking, and it’s why there seems to be so much arguing and bitterness within the community. Wolf didn’t “take the spot” of your favorite character. NeoGAF is fairly tame in this regard, but the amount of immaturity and logic-leaping exhibited at most of the other major Smash Bros. forums is alarming.
Would I like to see Ridley in the game as a playable character? Sure — he’s near the top of my wish list. But I’m not going to lose any sleep over his exclusion because I realize that he isn’t a high priority character, and I’m able to divorce my personal wants and wishes from the reality of the situation.
