Your statement is ridiculously contradictory and confusing.
The thing you have to realize is that the majority of characters in Smash 4 got straight nerfed, so the biggest buff to Mario is less about how he changed, but more about the rest of the game. Smash 4 Mario is basically a straight downgrade from Brawl Mario. We do less damage, our combos aren't super reliable still and percent dependent (we even lost proper Jab cancel combos), we're actually more easily juggled and edgeguarded, and we still generally don't have great KO moves. Rage helps Mario a lot, except good luck trying to actually survive long enough.
Pierce also believes Mario is bad last time I talked to him about this game. The only thing we do know for now is that "bad" characters in this game probably can win tournaments given the top tier is relatively weak. I mean...look at Ganondorf. He's not amazing, but he's getting results.
We get to debate again!!! But let me try to be clearer on what I mean. I realized I posted a lot of jumbled thoughts so now I'm going to outline it to make it clear.
To start off, I completely disagree with your statement that Mario is downgraded. Whether it's the mechanics of the games or the buffs Mario got, I believe Mario is stronger overall. From the moment I played Mario, I felt that he was much smoother and his moves connect better in this game. I really feel like I can get the quick hits, strings, and pressure that I want to create instead of getting interrupted like I did in Brawl. So while his hits may do less, you can connect more resulting in more damage. He also more better options to knock people up (utilt, dash attack, dtilt, dair). I don't see how he gets edge guarded harder. The fact that you can't hog the ledge instantly makes it easier for him to recover. Rage starts acting around 100%. Don't tell me you can't get to that percentage because if you can't, I will stop debating with you right now.
With that said, obviously Mario still has weaknesses. His range is still on the low side, his recovery is still mediocre at best, his kill power isn't that good, and he can get juggled. Mario had these same weaknesses in Brawl. However, most of these weaknesses I feel like are less severe. He has a slight range increase (not big though. range is still poor). I've noticed this with jab and utilt mainly. I already talked about recovering so I don't need to repeat. While still meh in the killing department, his kill power did increase. Back hit of Dsmash hits just as hard as front hit and his other moves I believe kill at lower percents (don't have numbers, but going off what I've experienced). Bthrow kills again. Rage also plays a factor. As for being juggled, it seems about the same except you can't airdodge into the ground.
As for Mario's spot on the tier list, I can't give you an exact place because I don't know the cast. The reason I don't see him as top tier is because I don't see him as a character that really dominates the game. Right now top tiers include Diddy Kong, Shiek, Rosalina, Lucario, and Ness to name a few. Mario is not as dominant as those characters. The fact that I can name 10 characters that I believe are better than Mario makes him not top 7. I'll name them if requested.
Hope this clears some things up.