first off, citing anything your peers have to say as the "whambulance" is hilariously dismissive and is a great way to have everyone dismiss you for being inconsiderate and shallow in your arguments. don't propagate this behavior.
secondly, link was hit with the nerfbat in 3.5 way too hard imo. the way that "good smash" is played generally involves a linear set of actions as follows:
1. since you don't want to get hit, you play a very cautious neutral game that involves establishing position
2. you achieve some kind of positional advantage such that the game state is risky for the opponent, but not for you, or if you are the one at positional disadvantage, you try to regain position and reset to neutral
3. you work your position into a conversion
4. you carry out the punish from the conversion optimally. optimally can mean many different things and goes past the scope of why link sucks for this post
you can deviate from this series of steps, but you are almost always wrong in doing so, especially as you get better and better as a player.
i submit that link sucks because he is wholly ineffective at every portion of this method. link's plan of attack in a match is generally to use projectiles to lead into a conversion, or to use projectiles to prevent a conversion from the opponent. 3.5 link is good at neither of these things. all 4 of his projectiles carry some (but not too much) risk from their slow and narrow use for each. more importantly, none of them transition into any reliable conversions, nor do they act as conversions the way say 3.02 boomerang did. for most characters, grabs are the default conversions, but 3.5 link's grab was already horribly risky, but now his throws suck too. grabs are essential to keeping an opponent honest from blatant shield abuse, and link no longer has any way to prevent this. the end result is that link can throw ****, but it has almost no offensive value at all since it can't reliably transition into a real punishment, and there's no way to resolve shield camping. the combination of these aspects means that nothing link has is threatening in any meaningful way assuming your opponent plays cleanly. and i don't mean plays well, i mean clean as in they don't jump into your upair strings. so long as your opponent doesn't punt and throw you a freebie, link is fairly harmless.
since we can dissect the character to a point where we understand that he doesn't have anything all that threatening, you don't really have to be as cautious in the neutral game either. this means that attacking link is relatively attractive as an option, because he's not really going to punish you in any meaningful manner if you screw up. since his projectiles are also worse at walling people out, you get to a point where you can just go in on him, since his main way of preventing being put into positional disadvantage and/or conversions is also horribly gimped. and let's be real link's combo weight and recovery aren't anything special and never have been.
so now you have this character that has a mediocre Plan A, no usable Plan B, and his Plan A sucks because you aren't really effective at killing people, and you straight up suck at keeping people from killing you back. this is why link sucks in this version. when you get a character that sucks at neutral, positioning, conversions, sucks against those things from real characters, and has a few major flaws along the way, you don't get a "thoughtful" character, you get a bad character that anyone above mid-level play can exploit all day long. i agree with the development team that balancing the game around a clear S tier like fox was no good, but balancing around D tier is no good either. strong bad says the game was balanced around the ideal A tier. with most of the cast, i can see what they were going for. with link, i respectfully disagree. 3.5 link is just a worse melee link surrounded by other, more numerous, more diverse, more complicated, real characters that don't have major flaws.
3.02 link was certainly good, but no where near being problematic. the only bad part about 3.02 link was the angle of boomerang being able to stuff well placed aerial approaches from peach, zelda, and jigglypuff, making those matchups overly-difficult. there was really no reason to address the rest of the character. i also find it particularly egregious that he was nerfed so excessively in a game where fox gets to STILL be fox. after like 6 versions of this game. like, are you kidding me? but i'll stop here since i don't want to make any comparisons if i don't have to.