Who where the top tiers of 3.0? From what I could remember, they included characters like Mario, Lucas, Pit, Link, Diddy, Mewtwo, and Fox. They all have really unique playstyles, and not one of them was really stealing the top spot at tournaments consistently (Mewtwo might be an arguable choice).
But anyways, I like how Lucas's U-throw was nerfed so as not to kill at 90%, Link was given more attention, and the only things that were really touched were the newer characters.
My two cents on Falco and Fox are that I like how the PMDT kept their speed of play, and only messed with move power and knockback. They kept that game pace because Melee is a fun game to play, and the characters are fun to play. The Melee high tiers have defined themselves already after 10+ years of people playing them. The PMDT respect this, I also support keeping their playstyles intact. I can't imagine a Fox that needs to camp. What makes PM unique is the larger roster and more balanced spread, all while keeping each character fun and unique. The new characters+melee low tiers are constantly being altered in order to make them able to fight toe to toe with the Melee high tiers, so a set playstyle isn't defined yet for them, so they can't be compared to Fox and Falco based on play speed, since maybe that's not the best way to play some characters.