I know we're not all going to agree, but here're my opinions:
Bowser Jr.
4/5 - Nice concept, and looks interesting too. Mario series is a bit oversaturated, but it's Mario, so that's ok.
Dr. Mario
0/5 - He could have easily been an alt costume, and the vitamins being a custom special. Lucina at least has different hitboxes than Marth, what is the difference here?
Shulk
3/5 - Don't know the series, but looks ok I guess.
Dark Pit
0/5 - If I could go negative, I would. Kid Icarus is way too overrepresented compared to Zelda (3 Final smashes between 5 characters?), Metroid (only 2 characters, who are the same person?), DK (No new stages in either version yet?), etc. What about Dark Link? Dark Samus? They've been around longer, and are also the same concept. DP started as a black recolor from Brawl, he is not important enough to Nintendo yet to beat out ANY of the unincluded characters.
Duck Hunt Dog
4/5 - Looks fun to play. They just better bring the laughing taunt in.
Wario
3/5 - Didn't have doubts, but nice to see him return.
Mr. Game and Watch
4/5 - No doubts here either, but he was loads of fun since Melee.
Falco
2/5 - He's still always played too similarly to Fox. Would have preferred Wolf since he at least felt different.
Ness
4/5 - Never been good with him, but he's always ben nice to have around.
Ganondorf
5/5 - Been hoping for this since the announcement of SSB4. I was wishing he'd get a different moveset or at least his glorious HW mane, but at least the King of Evil is back to play.
R.O.B.
1/5 - Never liked him all through Brawl, so I would have brought loads of characters back before him. He's not really a character from a video game so much as a toy they made to save the NES in the 80s, which Brawl's SSE wrote a backstory for causing them to cut Mewtwo.
Jigglypuff
3/5 - She's been a mainstay since SSB64, but I hope she's not going to stand in anyone else's way.
And the other characters I'm missing, which would make me like the roster if at least some were included, even as DLC:
1. Mewtwo: The only unjustified cut from Melee caused major fan uproar. Did they not listen to a large percentage of the fanbase?
2. Ridley: Another highly requested villain, who has been the subject of major fan teasing. It's just cruel not to include him.
3. K.Rool: Another villain from a severely underrepresented franchise, who has also been highly requested.
4. Wolf: He played quite differently to Fox/Falco in Brawl, and I'd really like to see him back. And that great attitude.
5. Ice Climbers: Yeah, I never played them, but they've been around a while and really grew on me.
6. Squirtle and Ivysaur: A nice dark horse from Brawl. Really liked their movesets, and I really want them for DLC.
I'd also LOVE to see some Assist Trophies get a promotion via DLC like Midna or Ghirahim.
Finally, I'd like if they spent more time with the already-revealed characters, so Link/Toon Link could have different specials; Zelda/Shiek with different final smashes; Ganondorf with a different moveset (give him the swords and then give the old moves to Black Shadow)