On the subject of wanted characters, I have two categorizations, which sometimes overlap.
1- Characters to which I have a personal affinity
2- Huge gaming icons that make Smash even more legendary
----- in this second category, the bar is lowered, but still present, for Nintendo characters (just about any new series will suffice, as well as true Nintendo All Stars)
Between these, in SM4sh and Base Ultimate:
Megaman, Pacman, Little Mac, Wii Fit Trainer, Villager, Shulk, Duck Hunt, Cloud, Ryu, Inkling, Ridley, SImon, Isabelle, King K Rool, Hero, Banjo and Kazooie, Terry, Min Min, Steve, Sephiroth, Kazuya, Robin.
(to juxtapose this, characters that i enjoyed, but didn't feel were needed- Rosalina, Bowser Jr, Palutena, Greninja, Incineroar)
And they all pleased me just fine. I do think Miis should just have been one character, but I suppose that could make it hard to tell the type of playstyle they would have, and make them perhaps, unbalanced, and for no less work.
Characters I would have passed upon: (well, in the context of other Pokemon, I would have chosen Meowth and Eevee over Greninja and Incineroar).
But I easily would trade in Ken, Richter, Dark Pit, Lucina, Chrom (for 5 more 'necessary' echoes, in my eyes... though I accept this for Ken, given his legendary status). I would absolutely trade in Corrin, Byleth, Bayonetta, Joker, and Byleth.
So, I honestly don't think I'm that difficult to please. I understand why Pythra got in- although I would never have chosen them. I understand Joker, only in the context that Sakurai loves Persona and wanted it in. I cannot reasonably explain Byleth, over so many other options, and blah blah blah which we have all heard before, and quite frankly, are based in fact.
So, yes, I think I am pretty easy to please. I have a wide net of characters I want, and could be perfectly content getting another fifty.
Fortunately, I have been able to narrow it down to a top ten 1st party and top ten 3rd party- though, I know those wouldn't inherently be the next ten of each, particularly as Nintendo hasn't honored an old Nintendo IP since 2014 with Little Mac.
In Ultimate, specifically?
I'd say my top ten consistently most wanted newcomers, from the Smash Ballot era until now, have been:
3. Dixie Kong
I'd still really love a fighter from an FPS or puzzle game, so I'm holding out hope that'll happen someday soon.
If you understand why they havn't added Dixie, please explain it to me. Homegirl isn't even an Assist Trophy.