I've been hesitant until recently to form a tier list of my own. Not only has 1 patch changed the entire meta's landscape, we've yet to truly experience the breadth custom moveset legalization will bring to the game as well. Despite my ignorance of some of the characters in the game, which I'll list below, and both me and my local community's support for custom moveset legalization, I've formed my own preliminary tier list for patch 1.0.4 with customs banned. I've been adjusting a notepad document on my desktop for a while now, documenting changes in my opinion since 1.0.4's release.
Characters I'm not comfortable placing yet include Mario, Luigi, Wario, Peach, Bowser, Ike, DHD, Villager, Lucario, Gunner, and Falco. I suppose I could pretend to have a refined opinion on all the characters' competitive value less than a month into the game, and have a complete list... but I'd rather have a more accurate list that reflects how I currently view the meta.
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-A Tier-
-B Tier-
(Maybe a few more)
-C&D Tier-
The rest of the cast.
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A Tier: I think these 4 are a small step above the rest of the cast, though Ness and Sonic follow close behind. They don't seem to particularly struggle with any very relevant matchups in A and B tier besides Diddy because their strengths more than make up for or cover their few weaknesses. It's difficult deciding on a cut-off point between A and B tier. Tiers represent rifts or distinct ideological differences between one set of characters and the next. The distinction I made between A and B tier is that I think you could easily go without a secondary with these 4 in patch 1.0.4 and win a national tournament, unlike those in B tier who have weaknesses that make for either somewhat of a volatile character or one with clear weaknesses that can be exploited in a variety of ways.
B Tier: I'm judging characters on whether or not they make it into this tier based on how likely I think they are to win large local or regional tournaments by themselves. Although characters with more polarizing matchup spreads like Villager, Megaman, and Rosalina are very unlikely to win large tournaments alone, I've accounted for the attribute of having higher than average matchups against some A or high-B tier characters, making them a fantastic counterpick option. For example, right now I think Rosalina very handily beats slow characters and/or characters with more linear approach options against Rosalina like Ness, Captain Falcon, and Robin, but struggles against speedy punish and/or trap characters with solid mixups like Fox, Sonic, and Sheik, or really anyone that can dispose of Luma quickly. Also, this tier is bigger than I've shown and I'll keep adding characters to it as I better understand the potential in some of the underused characters. This game is way more balanced than the other smash games, and it's necessary that the tier sizes reflect that. I'm very confident in my top 7- less so in the order past that.
C Tier & D Tier: Realistically, I think there's only 3, maybe 4 tiers. It's pretty crazy to theorize more than 4, imo, given how I separated each tier. I think it'd be really surprising, but not unheard of for any of the characters in my C&D Tiers to win anything past a large local, assuming the player isn't far and away more skilled than everyone else.
I'm ready to answer any questions about my list.