I'm going to digress to push back against a pet peeve trend.
It becomes culturally fashionable to retroactively double-down on the vilification of past top tiers. It's bad enough that players always-on-average exaggerate how broken the best characters are in the present. (In pretty much any game) But while some cases get lost to history with each new patch, others go on to be hyped up even beyond the exaggerations of their day.
There has to be
some qualitative truth as to how dominant or "overpowered" a character was/is. It's just hard to define and hard to compare, as defining exactly what measurement to use is subjective and comparing across different games is inherently flawed. But whatever that qualitative truth is, it's
nothing more and nothing less.
Last I checked:
was used by about 33% of players in supermajor top 64s at his peak; nothing more, nothing less.
was used by about 25% of players in supermajor top 64s at his peak; nothing more, nothing less. (Though he did perform more aggressively at higher cutoffs, coming close to Melee Fox's performance at certain threshholds)
(pre-patch) is hard to qualify; his
very strong momentum kept his players and results
increasing long
after patches 1.0.6 and 1.0.8 nerfed him barely half a year into his life. If I had to speculate based on the data we have, given enough time I would expect Smash 4 1.0.4 Diddy to reach ~15% of players in supermajor top 64s; nothing more, nothing less.
Barnard's Loop did a great deal of work on. I counted her as being used by about 6% of players in supermajor top 64s around the start of 2018, which almost exactly matches DasKoopa's stats of her being used by ~5.7% of ranked players in that timeframe. She climbed to ~10% in the time between that and Smash 4's release, bouyed primarily by secondary adoption by top multi-character users like Tweek. Nothing more, and nothing less.
Unrelated but related:
I still have no takers on my standing bet that in 2 years, no character in Smash Ultimate will enjoy over a 5% play rate across the competitive player base.
The pandemic got in the way, but we still easily cleared this limbo bar.
Across the entire bracket, every character has
under 3.0% usage by games. (By
player, the number would be slightly lower still.)
Across just the top 1/8th of brackets, every character is
under 4.0% usage. (Again, by games.)
In fact, even the
placement percentages landed at 5.0% after 1 year, before we got additional balance patches and DLC competition. (
Placements have continued getting more diverse, but it's hard to say how much of this is related to offline-vs-online play.)
Potential for further dominance is nebulous but there: ROB and Min Min are clearly on the rise, and Palutena seems like she is once again rising in popularity in spite of nerfs. Hypothetically Wolf could see an offline resurgence in the 11.0.0+ meta. Or Snake? I feel confident that the perennial "most overused" characters (Cloud, Ness, Bowser) are already close to their usage ceilings. I suspect Steve has a hard-ish ceiling too.
Really curious what happens next. Not to get anyone's hopes up, but 2020 saw the "big" balance patch (Min Min, with buff sets to 20+ characters) land in the summer following a previous smaller patch (Byleth) that included multiple nerfs. 2021 started with top-tier nerfs as well (with little in the way of changes to the rest of the cast), so my guess is that we'll see changes to other characters this summer now that the dust has started to settle at the top.
That said, Pyra came out over a month later than Byleth did, so anyone's guess as to how long we'll be waiting for the last 2 DLC and their patches.