Lucina is quite the ode to sub-optimality, but I'm not convinced she's the worst. I mean, on my current personal tier list, I have Marth at 35/51. Lucina is worse than that to a real extent, but there's no way she's 16 places worse than Marth since they do have the same frame data, the same hitbox shapes, and similar average reward on hit. In general I think people often underrank clones versus the originals; yeah all of the clones are the worse versions, but I don't think someone who errs and picks the "wrong" one is actually dooming themselves to lose as hard as a lot of lists make it look.
Speaking of tier lists, I kinda feel like we should get together what we're thinking about the game now; the balance very well may change a lot on the 15th, and it may be fun years down the line to remember what we thought of the game before its first major patch (1.0.4 doesn't really count since the Wii U version was the real version of the game and 1.0.4 was the same day). I suppose this is presuming 1.0.6 will actually change things, but it seems likely. At the very least, we're definitely getting a new character which of course could change everything. I've put some thought in, and here's about what I'm looking at which at some points does represent a lot of big changes since the last time I posted a list since my understanding has evolved a lot:
A+ (1): Diddy
A (2-8): Sonic, Rosalina, Sheik, Yoshi, Ness, Mii Brawler, Fox
A- (9-16): Luigi, Villager, Pikachu, Zero Suit Samus, Mario, Peach, Lucario, Captain Falcon
B+ (17-24): Link, Donkey Kong, Pit, Dark Pit, R.O.B., Shulk, Dr. Mario, Palutena
B (25-31): Olimar, Toon Link, Wario, Charizard, Meta Knight, Mega Man, Wii Fit Trainer
B- (32-39): Mii Gunner, Ike, Bowser Jr., Marth, Bowser, Duck Hunt, Robin, Kirby
C+ (40-44): Ganondorf, Lucina, Jigglypuff, Greninja, Samus
C (45-50): King Dedede, Pac-Man, Falco, Little Mac, Mr. Game & Watch, Mii Swordfighter
C- (51): Zelda
Time to qualify this list massive:
This assumes customs on; that's the game I play. Stage rules are assumed to be similar to EVO's (FLSS). This is ranking characters in terms of their viability as a dedicated main; obviously Little Mac especially has more value than this as a secondary, but he's way too easy to counterpick/stage strike against to have more viability as a main than that (I feel like Duck Hunt as well would rank much higher on a tier list of "value as a secondary"). This is also about how good I think the character actually is, not about how popular a character is. I already know I'm controversial on a few characters (I really don't believe in Greninja or Pac-Man at all), but the way I look at it, there are a lot of good characters in this game and moving someone up means implicitly moving everyone else down so if I rank a character low it's me paying a compliment to everyone I rank above them. Like it kinda killed me to put Falco in bottom five except I didn't want to move any of the 46 characters above him down... Also, to be clear, I think anyone with either an A or a B is a truly viable character, and I think all of the Cs are good enough to be dangerous even if they are flawed in various ways. This means match-ups against most of the cast matter; Sheik is a bit better than Rosalina against other characters in top 5, but I think Rosalina outperforms Sheik sufficiently against characters outside of the top 5 to just edge Sheik out on the list (but it's close!). Obviously as one guy my knowledge is imperfect, but I feel like this is the best, most honest representation of how I see this game's balance that I can provide.
I can explain what I'm thinking about any of these placements which could be a fun discussion, but just as much, I'm curious what sorts of lists other people are keeping. Like I said, we may be happy to have this stuff documented in a few years when no one remembers what this version of the game plays like. It would also be interesting to see where we all actually agree and where we all disagree.