I can't really speak much regarding competitive/tournament play, but it seems almost as if everyone unanimously thinks Zelda is a terribad character in Smash.
I... tend to really disagree. Zelda (Not Sheik though they're both good) was my secondary in Melee. Honestly, there were times she was my main. Her and Roy routinely competed for the spot, but in the end Roy was my favorite.
In Brawl, I got enough newcomers that I absolutely loved (Ivysaur, Lucas, Olimar & ROB are easily my favorites) that I kind of abandoned Zelda. Not because she was bad, but because she wasn't as good for me as some others.
In Smash 4, I'm pretty concerned about losing Ivysaur, Lucas, and to a lesser extent, ROB.. So up until Robin, Zelda and Olimar were the only characters I was thinking about seriously.
She's strong. She's got fantastic air game. She may be a bit slow, but honestly that's just not all that important. I'm not going as in depth into things such as landing lag and such, but I feel like she really is underrated as a whole. I can wreck with Zelda far better than I can wreck with Fox in Melee or Meta Knight in Brawl (Actually, Meta Knight is probably one of my worst, perhaps I am only worse with Lucario)... I just don't get it. But I guess you guys will throw some technical stuff at me (Like when people try to tell me that Marth was better than Roy, lol) or something. I just completely disagree.
It's great that you like Zelda so much, and I agree that she's super fun to play and can do some damage in the hands of someone who knows how to play her!
However, it's just unfortunately
true that she is, compared to most characters in Melee/Brawl, not as good. Her aerial game is, unfortunately, not "fantastic" - three of her aerials are only useful when speetspotted, and only have a very small, one frame long sweetspot. Her up air is slow to start and slow to end, easy to dodge and easy to punish. Only her nair could possibly used to rack damage and give her something of a safe/non-super situationally good aerial - but even it is hard to land due to its strange hitbox that tends to hit too high and at a strange angle. Her sweetspotted aerials are
fantastic kill moves - but sadly, they're hard to land, unsafe, and don't allow for any followup damage.
Her smashes, while seemingly strong as they are all fairly quick, do good damage, and have good knockback - are hindered in that two of them (forward and up) are multi-hit moves that are very easy to SDI out of, so she's not going to get the full damage or the strong final hit knockback - and is probably going to get hit as she finishes the long animation. This leaves down smash as her only fully reliable smash attack - but it is very good, I can't complain about it at all.
The lack of good aerials very much hinders her options of "approach" - it is hard to go on the offense as Zelda as you have to try to get close without any safe way to do so. This wouldn't be as big of a problem if she had a good projectile she could pressure opponents with and force
them to approach
her. Again, Din's is her only projectile (though now she has Phantom, so we'll see what happens with that!) and it is slow, easy to dodge, and leaves her vulnerable due to its high ending lag - and not only this, but it leaves her helpless in the air - gimping her off-stage options and leaving her open to getting hit even more easily if she uses it in the air on stage for some reason.
Farore's Wind, while a long-distance recovery, is not necessarily a very good one. It's... not the worst, per se, but it is very rigid in that it must travel in straight lines, doesn't automatically make her grab the ledge, gets stuck on obstructions, and allows for almost no horizontal movement after using it - meaning it will either fail to get her back to the stage due to lack of horizontal movement, or force her to travel straight down into a planned attack.
Add in the facts that she is tall,-and therefore an easy target for more moves and easier to hit sweetspots on - floaty, - meaning her aerial movement is slower, easier to gimp, and easier to KO - and fairly light - obviously meaning she gets knocked further earlier - and she simply has an unfavorable stat spread as well.
Now, I think that in the hands of less "technically" oriented players Zelda can be a very strong pick. For players who don't focus on shielding and dodging, Din's Fire goes from a move that almost never hits to one that almost always hits, and her smash attacks go from almost never being finished to almost always hitting and finishing with the full damage. In more technical play though, she is simply outclassed by many other fighters due to a bunch of unfortunate attributes that add up and bog her down.
Don't get me wrong, I
love Zelda, and she and Ness are most definitely my Brawl mains - and I probably play more Zelda than I do Ness, overall. I just know what limits her and why it's so difficult to beat someone of the relative same skill level one-on-one if they're playing another fighter. I don't want to sound like I'm saying that I don't think Zelda will ever be good, because I think that Smash 4 Zelda is shaping up to be much stronger than Melee or Brawl Zelda - but I also know that she has a lot of obstacles to overcome, and a lot of technical issues that make her more difficult than she should have to be.
Sorry if you feel like I just threw a bunch of "technical" stuff at you, but that's really the reason she's so often looked down on - because honestly, if you're not playing with "technical" things in mind, she's actually quite good. The only way to really see why she's held so poorly is because the competitive community
is talking about playing very technically, and within that style of play are the things that hold her back.
So yeah, I agree with you that I don't think she's very bad at all outside of competitive play. I've seen a lot of people seethe with rage when she's able to win by spammin' that Din's Fire and it never gets dodged, and I've seen a lot of people wreck with her smashes when they're not SDI'd out of. A lot of my casual player friends think she's "cheap" and overpowered, actually! It's really just when the technical stuff comes in that her faults seriously show.
But I'll always love and play her regardless of her tier placement, and I think things are looking up for Zelda fans in Smash 4!