You've hated Nasus for that long, fine. I've hated Lee Sin for a similar amount of time just because I was so kitten sick of seeing him in games.
Splitting hairs here, but Nasus isn't a tank, but tank_y_. He's no meaningful damage mitigation/defensive steroid outside of his counterable sustain, and he's only got one crowd control ability. He's a damage threat, who builds tanky to facilitate their damage. A Juggernaut.
Lee was meant to be a duelist, yes. But he was able to get to that duelist strength without really meaningful trade-offs in return, given his mobility especially way back when compared to others. And that's why he was hit; he was meant to be a duelist, but he was too good at it in pretty much all situations.
You actually did complain about Wither being a ranged move, when you were doing the Boards thing of listing most a champion's kit, embellished with a little hyperbole, and saying it's OP.
Although, once again, I do agree with you that his ult change is really nice to use, but it might have too much power concentrated in it. And if any part of his kit is hit, we might have to see some fabled compensation buffs; I know that plenty people wouldn't be happy with that. His kit really hasn't aged well, it's still chunky and rough around the edges, the Spirit Fire buffs were amazing and all I had hoped for, but the ult changes were just gravy.
Also as a side point, Merc Treads cuts 1.5s off of the duration, which is correct! But there was already a 1 second window of downtime. So there's a 2.5s window of downtime now with them. I'd say that's a pretty huge jump from 1s, especially given how bursty things are these days.
When you point out the numbers of someone and whine about how strong they are, of course they're gonna seem strong.
You're missing the fact that he has to get to you to hit you for those numbers. And it's supremely easy to kite him these days unless he gets the drop on someone.
So yes. I'd call him balanced. Because he's really, really weak to being kited. He has to run towards folks, since he's got no dashes and nothing like Darius' Apprehend or Yorick's wall. They've decent payoff for getting in on folks, so he should also have a fair payoff for getting in on someone. And he does. (Also a 48.7% winrate according to OP.GG, the fact that he's not brushed 50% winrate since patch 8.5, and the fact that his winrate climbs fairly proportionally with game length as his design intends, lets me feel satisfied in calling him balanced.)