Easiest to hardest:

2D/2.5D
1. Phantom Hourglass
2. Spirit Tracks
3. Minish Cap
4. Oracle of Seasons
5. Link’s Awakening
6. Oracle of Ages
7. Link to the Past (best)
8. Zelda 1
9. Zelda 2
3D
1. Twilight Princess
2. Wind Waker
3. Ocarina of Time
4. Majora’s Mask (best)

The hardest are usually the better ones (except 2 and maybe 1 for using such cheap difficulty)

ZELDA: no help, you need the map, not linear, you respawn at the first screen, the save system sucks
ZELDA II: points system, points can be taken away, save system sucks, points can be erased, you respawn at the temple
MAJORA'S MASK: time limit, errands, cycle, prologue, not keeping money
FOUR SWORDS ADVENTURES: not keeping anything, limited saving, you can only progress if you have the Power
WIND WAKER: sailing
PHANTOM HOURGLASS: sailing, temple of the ocean king

Sailing isn't hard in Wind Waker. That's the least challenging thing in the entire game.

Yeh, while riding on your grappling hook, you use the King of Red Lions to move through the wind while you sail retrieves treasure from the ocean.

I included things that make the game frustrating and/or tedious.

1. The time limit doesn't make the game tedious. It gives the game a sort of action feel and makes you strive towards actually getting things done. Find shortcuts, get items, and discover secret pathways so you can still make it further once you rewind time. There's also a song that helps you... wait for it... slow down time!
2. You don't have to do the errands...
3. Cycle?
4. I admit that the prologue was a bit tedious, but it was nothing too difficult and it gives you a feel for the fast-paced frantic action that will later come in the game. The storytelling and dark undertones make up for it in every way, though. Once you pass the prologue, you're ready to experience the sauce of the awesome variety.
5. There's a bank to store your money in and the game practically throws rupees at you. Rupee harvesting is easy especially when you get certain masks that make you go faster.

So yeah, I find your argument very invalid.

Phantom Hourglass
9.5/10
Very Easy.

Hardest : Zelda 1 ,2 and Majoras mask (maybe not the main quest but a lot of those side quests left me v.stuck )
Easiest : Spirit Tracks

The Ones I've Played, using a more logical scoring system.

ALttP- 9/10
LA- 5/10
OoT- 7/10
MM- 9/10
WW- 6/10
MC- 5/10
TP- 5/10
PH- 3/10
ST- 4/10

Easiest to hardest:

The Legend of Zelda: The Wind Waker

Haven't finished the others yet. '__'

Easiest to Hardest:
The Legend of Zelda: Spirit Tracks, The Legend of Zelda: Phantom Hourglass

I recommend Majora's Mask. Play it through 3 times, then move on.

Let's see 'ere...

Easiest to hardest:

Ocarina of Time
Wind Waker
Majora's Mask

1=easiest 10=hardest (makes more sense to me )

Zelda 1: 8/10
Zelda 2: 10/10
Link to the Past: 2/10 (I can collect EVERYTHING without even meaning to. Probably because I've played it so many times.)
Ocarina of Time: 2/10
Majora's Mask: 5/10
Wind Waker: 4/10
Twilight Princess 1/10

Zelda 2 is easily the hardest, while the only time you should die in Wind Waker is if you fall asleep while sailing.

Ocarina of Time: 5/10 - The only hard part was the 100 skultalas.
Majora's Mask: 6/10 - Mainly for the Kafei quest
Windwaker: 3/10
Minish Cap: 4/10 - Kingstone Pieces!!!
Twilight Princess: 2/10
Phantom Hourglass & Spirit Tracks: 3/10 - Mainly for collecting all the ship/train parts.

1 = easy 10 = hard

Legend of Zelda: 9/10
Zelda 2: 10/10
A Link to the Past: 7/10
Ocarina of Time: 6/10
Majora's Mask: 7/10
Wind Waker: 1/10
Twilight Princess: 3/10

Even though great games, it's a shame that the latest Zelda games haven't had too much challenge.

Legend of Zelda: 6
Zelda II: 9 (Really hard, at least for me.)
A Link to the Past: 7
Ocarina of Time: 7
Majora's Mask: 9
Link's Awakening: 9 (played when I was young and was incredibly difficult for little PaupackElite)
Oracle of Seasons: 8
Oracle of Ages: 7
Wind Waker: 8
Minish Cap: 3 (Too easy and short)
Four Swords Adventures: 5 (havent beaten it yet
Twilight Princess: 5
Phantom Hourglass: 7
Spirit Tracks: 8

It's hard to really say because some of the games I used a guide, like Ocarina and aLttP, so that may affect the difficulty looking back. My favorites are probably the Game Boy ones, not counting Minish Cap.

TLoZ using the better way 6.5/10

1=Easy, 10=Insanity
Zelda 1: 10
Zelda 2: 11
Link's Awakening: 6
Ocarina of Time: 9
Majora's Mask: 10
Wind Waker: 8
The Minish Cap: 7
Twilight Princess: 8
Phantom Hourglass: 6, but the infuriatingly-unresponsive Final Boss controls make it go to an 8
Spirit Tracks: 8

im thinking on going to Links Adventure DX or Oracle Ages / seasons

on those three, wich one is more challanging (pluzze wise) ?