Zelda isn't bad you are just using her wrong.
I wanna start by talking about...
Din's Fire, AKA Dins.
There is no data on Din's fire from teh zelda boards as far as I can tell :/ but the move is significantly faster than you would think. Test it out and play around with it. Aerial Dins may end faster than grounded... but I'm not sure 100% on that.
At first glance Dins is a bad easy to read easy to punish easy to dodge projectile. This is because people use it very predictably.
Dins has tons of nice attributes, when used in the air I acts a a vertical stall. but you still maintain a lot of your horizontal momentum. this allows for powerful mix ups on landing (especially when combined with Nayru's Love) that give you an active hit box in front of you to further cover you landings against people running and/or jumping at you to punish your landing.
Another note: I strongly believe Dins is use at a zoning tool. think of it like a ranged version marth's fair. A huge disjointed hit box normally I put it off just in front of my opponent so that it will hit their shield. but you can detonate early late etc. Once you start reading habits you can use din's to punish them. for example if people always spot dodge once my dins gets to a certain range I'll wait and pass it through the and detonate to punish the spot dodge.
I'd also suggest as Dins moves further away you move it further up. this will help to cover jumping options better and if you pull it back down after you start to pass them they are in din's range longer than they would have been other wise.
Din's biggest strength is against opponents in the air. Dins (especially at higher percents) forces literally forces air dodge detonating early will often times give you the opportunity to punish these air dodges with moves like dash attack usmash and uair nair LKs etc..
your goal in using Din's should rarely be to hit your opponent but corral, condition, and contain their movements; to stop approaches you can't handle and force sloppy approaches and force better of two evils types of situations
Naryu's Love
Back in the melee days we called this move Love... at least I did...
this move is good and bad... it'd be amazing if the invincibility and hit box over lapped... but they don't.
Love can be use in place of spotdodge although the invincibility window is significantly smaller you can sometimes punish things that you otherwise would be unable to, but thats rare and risky because of the lack of invul overlap... and the smaller invul window.
the main way is as a mix up for my landing. Though shield will almost always beat Love (Love can shield poke people with meh shields.) it is nice when people are expecting to punish you with a grab or short duration anti air move.
you can also use it as a very powerful anti air that'll beat pretty much anything spare stalls and nades. because of it's huge range it can cover many more options than usmash. the invincibility covers all landing attacks. So if say... falco is falling towards with no jumps you think he is going to try for a spaced bair or an air dodge in his landing you can throw out Love and beat both options and probably get him off stage at a low angle.
Defensive
Obviously Zelda has a very very powerful defensive game with moves like usmash dash attack jab and fsmash and Dins getting inside of her zone can be very difficult. What she lacks in ground speed she definitely makes up for in air speed. And though her air game isn't the most impressive with her air speed and mobility it isn't something to play around with because of the LKs and nair. When combines with Din's it allows her to very safely position herself how she wants even against very aggressive opponents.
Its your job, as Zelda, to force them into a position where they need to enter that zone even if you are behind in stocks or percent. How do we do this?... apply pressure walk up to you opponent and force them into that scary zone. use dtilts jabs and fsmash to safely apply shield pressure.
Approaching
I depends... Zelda's approach game isn't as terrible as people would like you to think. she is slow, but she definitely has tools to bait punishable and condition reactions. As zelda you really want to work hard to get the advantageous position, the won't always necessarily come in the form of an approach. mix ups and reads are going to be huge for zelda.
dash in fading dins
dash in grab
dash in sh nair
dash threw sh bair
dash in sheild out side of their range charge fsmash
be creative, zelda isn't sheik (or any character) you have to take time to fully understand her moveset AND her limitations, learn whats safe and more importantly what isn't. (Fsmash isn't safe on shield, Usmash isn't safe on sheild)
I wanna start by talking about...
Din's Fire, AKA Dins.
There is no data on Din's fire from teh zelda boards as far as I can tell :/ but the move is significantly faster than you would think. Test it out and play around with it. Aerial Dins may end faster than grounded... but I'm not sure 100% on that.
At first glance Dins is a bad easy to read easy to punish easy to dodge projectile. This is because people use it very predictably.
Dins has tons of nice attributes, when used in the air I acts a a vertical stall. but you still maintain a lot of your horizontal momentum. this allows for powerful mix ups on landing (especially when combined with Nayru's Love) that give you an active hit box in front of you to further cover you landings against people running and/or jumping at you to punish your landing.
Another note: I strongly believe Dins is use at a zoning tool. think of it like a ranged version marth's fair. A huge disjointed hit box normally I put it off just in front of my opponent so that it will hit their shield. but you can detonate early late etc. Once you start reading habits you can use din's to punish them. for example if people always spot dodge once my dins gets to a certain range I'll wait and pass it through the and detonate to punish the spot dodge.
I'd also suggest as Dins moves further away you move it further up. this will help to cover jumping options better and if you pull it back down after you start to pass them they are in din's range longer than they would have been other wise.
Din's biggest strength is against opponents in the air. Dins (especially at higher percents) forces literally forces air dodge detonating early will often times give you the opportunity to punish these air dodges with moves like dash attack usmash and uair nair LKs etc..
your goal in using Din's should rarely be to hit your opponent but corral, condition, and contain their movements; to stop approaches you can't handle and force sloppy approaches and force better of two evils types of situations
Naryu's Love
(<3 Note: I think every thing is off by 1 frame here...)Nayru's Love
Hitbox Active: 13, 16, 19, 22, 25, 28 (6 hits)
FAF: 60
Invincibility: 5-12
Reflects: 5-42
Damage: 1/1/2/2/1 (first 5 hits), 5/5/4/4/3 (final hit)
Back in the melee days we called this move Love... at least I did...
this move is good and bad... it'd be amazing if the invincibility and hit box over lapped... but they don't.
Love can be use in place of spotdodge although the invincibility window is significantly smaller you can sometimes punish things that you otherwise would be unable to, but thats rare and risky because of the lack of invul overlap... and the smaller invul window.
I use it a few different ways.
Spotdodge
Invincibility: 2-20
Total Duration: 25 frames
the main way is as a mix up for my landing. Though shield will almost always beat Love (Love can shield poke people with meh shields.) it is nice when people are expecting to punish you with a grab or short duration anti air move.
you can also use it as a very powerful anti air that'll beat pretty much anything spare stalls and nades. because of it's huge range it can cover many more options than usmash. the invincibility covers all landing attacks. So if say... falco is falling towards with no jumps you think he is going to try for a spaced bair or an air dodge in his landing you can throw out Love and beat both options and probably get him off stage at a low angle.
Defensive
Obviously Zelda has a very very powerful defensive game with moves like usmash dash attack jab and fsmash and Dins getting inside of her zone can be very difficult. What she lacks in ground speed she definitely makes up for in air speed. And though her air game isn't the most impressive with her air speed and mobility it isn't something to play around with because of the LKs and nair. When combines with Din's it allows her to very safely position herself how she wants even against very aggressive opponents.
Its your job, as Zelda, to force them into a position where they need to enter that zone even if you are behind in stocks or percent. How do we do this?... apply pressure walk up to you opponent and force them into that scary zone. use dtilts jabs and fsmash to safely apply shield pressure.
Approaching
I depends... Zelda's approach game isn't as terrible as people would like you to think. she is slow, but she definitely has tools to bait punishable and condition reactions. As zelda you really want to work hard to get the advantageous position, the won't always necessarily come in the form of an approach. mix ups and reads are going to be huge for zelda.
dash in fading dins
dash in grab
dash in sh nair
dash threw sh bair
dash in sheild out side of their range charge fsmash
be creative, zelda isn't sheik (or any character) you have to take time to fully understand her moveset AND her limitations, learn whats safe and more importantly what isn't. (Fsmash isn't safe on shield, Usmash isn't safe on sheild)