Mewtwo would have his own plot. Stoip being idiots people, we can have 5 POKEMON FOR GOD'S SAKE! Seriously-Mewtwo would work better then almost any character (better then any Pokémon) in the SSE. ANY GOOD REASON MEWTWO SHOULD LEAVE=???
1. Everyone knows him.
2. He's more popular then Lucario and Jiggs combined.
3. UP there in the top 5 most popular Pokémon with Charizard (Pikachu is #1).
4. Has so much originality potential.
5. He is the strongest Pokémon statwise tied with 5 other Pokéball'd/bossified Pokémon.
6. A full psychic moveset=win.
7. He's got MASSIVE general fanbase.
8. He's got MASSIVe pro-Brawl fanbase.
9. Before everyone found out he sucked, everyone played him. I played Brawl at a EB games 2 weeks after it came out, and everyone else played him (there were 50+ peoples). I played Kiby. Ya, I wasn't much better off. >_>
10. Because Pokémon deserves 5 reps. We have 4 confirmed-and 1 more seems very likely.
11. Lucario and Mewtwo are nothing alike.
12. Mewtwo is a original character, despite being a Mew clone.
13. Mewtwo has a original moveset. LUCARIO IS NOTHING LIKE MEWTWO! XD
14. His roll in the SSE has lots of possibilities. He could start off being a villian, then be a hero.
15. Because he's the strongest Pokémon. Go check his Pokémon biography! XD
Now, do I have to go preach about Mewtwo in Brawl on your a**es again, or what=??? Don't make me pull out ma psychic powerz! Plus-Mewtwo needs his bottom tier REVENGE!
MEWTWO FOR TOP TIER!