There are a few issues with trying to do that right now:
1: We need top level mains for each character to contribute to the conversation. Some characters have very few players who play them at top level. And even the ones with good representation can be hard to get a hold of and it takes a ton of time to get a consensus on matchups.
2: By the time a matchup spread is generally agreed on, PM gets updated and the old data is largely worthless.
Basically, a worthwhile tier list will not be possible until PM stops updating.
Aside from the handful of characters that receive significant changes in any given patch, I think updates have begun to take a back seat to plain old metagame development. There are still quite a few characters for whom the top players, let alone everyone else, are often fumbling around with things that are unlikely to have any real significance in their gameplay given another year or two, let alone five. It misrepresents that character's potential. Then you have complications with gaps in fundamentals and matchup knowledge, compounded by potential for ongoing development on the other end of that matchup...
Number tweaks as simple refinements in design usually don't have huge impacts. Big changes that add/remove/rework use cases for certain tools, that's a different story.
For now I think it would be a better use of time to analyze the characters generally agreed to be more glaringly in need of tweaks to bring them up or down in viability (Olimar, Pit, Bowser, Yoshi, Fox, Wolf, are some in my opinion).
Where it's like general discussion about frame data and damage and even just bad/great moves and how we could change them.
Like I enjoy the tier list discussion but it's never really about tier lists directly, unless it's us just picking apart some noobish tier list for fun. It always turns into single character discussion and occasional matchup discussion anyway.
There's a fantastic post on /r/ssbpm right now about Yoshi, detailing problems with his hitboxes and small design changes (and potential fixes).
For the most part I think this is what the PMDT is already doing, aside perhaps (read: hopefully) from the motive of "bringing them up or down in viability". No character is entitled to being mid tier, let alone high/top/best-in-class. On the other hand, a specific character consistently performing well is not inherently bad. The reality of having 40+ diverse characters is that some are just naturally solid and probably always will be unless you gut their core, which is undesirable. Design comes first, and it tends to address balance in the process anyway. If you start with the goal of giving everyone a complete set of functional tools, then play with the strengths/weaknesses/applications of those tools in fun and interesting ways, the result can still be both diverse and balanced. It also leads to healthier, more stable balance, a more focused design process, and overall a more fun game. Actively trying to make a character better or worse instead of giving due priority to design considerations and following the path that emerges can have undesirable results, something we've seen in action a few times now. It creates problems of its own, even if they're not always readily apparent.
We've generally seen the game progress in a clear and consistent manner towards a particular goal over the past few patches. A few missteps, a few things that perhaps have overstayed their welcome, but mostly on the right track. A lot of the current "issues" don't necessarily represent balance problems long-term, but they're arguably just as important, maybe even moreso, as who's at the top or bottom of the list. I'd actually argue that the top tiers are pretty close to okay for the most part. Small tweaks in the right places as needed + design improvements to characters that could potentially give them trouble with a solidified kit will see them comfortably "in the mix", so to speak. The bottom tiers just need a few gaps filled to be solid as well.
Discussion has intuitively followed in that direction. The difference between top and bottom is close enough and the thread of design is clear enough to favor thought and discussion within that vein. As such, the thread naturally manifests as a sort of barometer for certain topics of interest. It'd be interesting to chart the frequency of different words appearing over time in this thread - different characters, moves, mechanics, etc.
At any rate, I wouldn't mind seeing the thread renamed. Tiers are still sort of relevant to the discussion, but usually in a more secondary role. The discussion itself is already doing what it needs to do.
By design, probably Lucario. He can work relatively consistently with a wide range of characters and percents. It may depend on whether you consider "brutal" has most number of hits per combo, most damage per combo, strongest guaranteed finishing move, etc. though.
I honestly don't know about that anymore, or at least wouldn't put him out in front by any noteworthy margin. His combos are fast and flashy, sure; yet I think there are clear limits to what he can do, and that these limits will become more apparent as matchup knowledge and experience proliferate. Aura just gives him means to push that limit a little further back. I'd instead point to
consistency as a notable strength in his punish game. If he opens you up, he's going to get something worthwhile for that effort.