I don't think auto sweet spotting should be removed... Every character can rise above the ledge nullifying the auto sweet spot if the joystick is held at a downward angle. This way it's strategic in that you can choose whether or not to auto sweetspot. To me it doesn't make sense to systematically remove auto sweet spotting as it helps some characters more than others, why deny characters who need it more than others?
I just think it's a waste of coding space, and otherwise lame.
As you said, Brawl+ tiers will be nothing like regular Brawl. CF is low on Brawl, yet I easily see him being High/Top tier material in Brawl+...
Despite Falcon's wealth of comboing potential I highly doubt that's enough to consider him top tier. He still lacks priority, as such, I don't see it possible for him to reach top tier (or even high). Most characters keep him at bay with moves that greatly out prioritize his attacks. For example, Falco's short hopped double laser, or even single short hopped lasers make his approach game an extremely difficult one. Then there are characters like Marth who have no projectiles yet a simple Fair will out prioritize most everything Falcon can dish out.
There's simply no way Falcon can be a candidate for high tier.. and especially not top tier, if he had more priority sure, but that's not the case. Every character gets better with hitstun some more noticeably though than others. Take Fox and Sheik for example, both were mid tier before, but with hitstun there's no denying the fact that they are top tier quality now. Now let's pit Sheik against Falcon, she can combo him into oblivion, and she can easily stop all of his approaches with spacing and her tilts. It really becomes a one sided match. Trust me, my friend plays Falcon and doesn't see it possible to plausibly defeat a competent Sheik (such as myself) or a consistent basis.
Obviously Fox and Sheik are just a few of the characters who noticeably jump tiers, though I'm sure many others do as well. Captain Falcon for example looks to be a character that was meant to play in a world with hitstun, as such, he's probably higher on the tiers. To say the least, he's certainly not bottom tier at this point.
In addition, Brawl+ actually has more characters than Brawl, as far as tiers are concerned. Thanks to the pokemon infinite stamina and no switching upon KO codes Squirtle, Ivysaur, and Charizard are all very capable stand alone characters. We have 39 characters to rank instead of Brawl's 37. Originally we had no choice but to view Pokemon Trainer as a single character thanks to switching pokemon upon death, and the fact that switching was necessary thanks to stamina. We had to consider him a unified character, 3 in 1. Now, thanks to each pokemon's new found viability we can consider each one there own character. Similar to how we treat Zelda/Sheik as their own characters because they don't HAVE to switch in the match, they can be played alone, we MUST now treat Pokemon Trainer the same way. With that said, who's to say that Squirtle isn't high/top tier material?