Let me address some of these points, because this is getting kind of old.
Sackboy isn't especially nimble.
He doesnt have to be. He is nimble enough at his Super 3, when no one can stop him. His gadgets allow him to move quick enough. He is one of the more quicker players in the game
The teleport requires him to set it up ahead of time, meaning he'd have to drop it and cross the entire stage, which he's bad at.
Not as hard as you make it sound. Nor does he have to move himself with the way you get thrown around in this game. He can reach high spots and place spawn points anywhere. I dont recall if he can do it while using his Super 3, but it's not difficult to set up spawn points to up his maneuverability considerably for a super 3
And he still has to get the meter in the first place, which he largely earns through tagging people with cakes and jam. These are just not hard to avoid, and his combos are nowhere near as high-earning as other characters.
Just like everyone else, but with less of a requirement. His combos dont NEED to be high earning when his requirement is much lower. Nor is Sackboy a combo character. His trap moves more than make up for this. Funny enough, I'm pretty sure you can combo with Sackboy anyway
I also see no issue with a character being based on going for the higher level supers. Why would that be a problem? Different characters should play differently. Sackboy's level 1 is tricky to use, and while his level 2 is great it's only _so_ much further to 3 after, so I can understand that decision. And a lot of characters have good level 2s and 3s, Sweet Tooth is just a terrible example. I'd know, I play him.
You missed my point regarding: AP gain, AP requirement, ease of use, reliability, and dependency. If you dont want to use Sweet Tooth, I feel that most the other roster works just as well when it comes to the fundamental issues people have with Sackboy. Raiden, E Cole, Jak, Kratos even, Fat Princess, Screen Kill characters (who u admit have the same AP requirement, but only get 3 kills), Sir Dan, Nariko, Dante. All of whom have super 3's that can be dodged, all of which have a weakness that puts up a challenge. All of whom have to work harder to get to their supers, none of whom get rewarded bonus AP for whiffing their super.
As far as the level 3 itself goes, yes, it's undeniably better than some.
It's undeniably better than all
But a major reason for that is because Sackboy's other supers are iffy, like I said.
No, they aren't. If he can hit confirm his super 1, then he really becomes an all around character. Regardless, his Super 2 is really good, since it can be placed at will precisely, and with the scaling of his Super 3, the interdependency of both supers removes any major risk of going and failing to reach a super 3.
You can pretty much guarantee a kill or two with the level 2, but he lacks proper setups unless someone lands on an electrical pad.
Not true, he can place that super down in really tight situations, guaranteeing kills
He also only has hitconfirms with the level 1 against like, 3 characters.
To use your example, Big Daddy has a level 1 with setups (though it's still not a great super), a level 2 that has the potential for high payoff, and actual combos, armor, etc. that let him hang in a fight. And the success of any multikill level 3 is very reliant on the stage. On a large stage like Stowaways or Columbia, Sackboy is going to have to run around and catch people who are scattered everywhere, giving other players a chance to float up. Yes it's slow, but it's not useless. And he's only going to have a maximum of one teleport because that's just how it works.
As it stands now, I dont feel like he should be able to hit confirm at all considering how easily he can build to his super 2, he's got enough going for him, but that's overly harsh and besides the main points of criticism.
Big Daddy's level 2 can be dodged more easily, requires more timing on your part, can be countered and even can backfire (falling off a stage, bumping into things). And it's a much better alternative than his super 3 all things considered. Your point about the success of the stage is relational, if Sackboy has a hard time, so does everyone else, but in relativity, Sackboy always has an easier time than most others. The simple fact is that even if he somehow screws up the super, he GAINS AP-- his super 3 rewards him with defenseless players, items, and free AP. This point still stands. His requirement is ludicrously low. He can quite nimbly get those that float up with his teleports, jump pads, and grabinator-- compare this to Big Daddy's super 3. One teleport is one too many when it comes to his Super 3, and guess what he's doing in between all that time chasing players? Gaining AP and items for himself and his partner.
I just think it's ridiculous that people are acting like he's unquestionably the best character.
Who do you think is the best? He most certainly tops the list along with Kratos. It's simply the fact that Sackboy is a less input/highest output character. You put relatively less work into a character like Sackboy and somehow gain more than other characters.