MM was a very good game, AND a very good zelda game, it was just short, and due to the tense atmosphere it represented, many people didnt like it. you couldnt just run around and enjoy/explore the land, becasue everything was by the clock. but it was a well-made and very challenging game.
on to this topic, i believe what a zelda game needs to make it better than
OoT is something new. the isometric camera angle for the dungeons and horseback fighting will already make it a good game. but yes, it needs something new.
tWW had a more fluid method of battle than
OoT, but
OoT was still better because the bosses were harder, and it was bigger and had more dungeons.
Z'05 will need the following things to amke it better than
OoT:
1. 7-9 dungeons
2. an in depth battle system. by this i mean a lot of different variety in the enemies, and lots of ways to tackle the situation with your various items.
3. secrets need to be obvious in existance, but difficult to reach. eg. i want to see a large boulder in a wall in the first village of the game, but be unable to blow it up until about 2-5 dungeons in.
4. a complex, multi faceted story, that follows the development of more than just one character (eg. at the start of the game a little villager child is a scared coward, and towards the end he grows and matures and sticks up for himself)
5. a filled up land (by that i mean ther always has to be something of interest and landscape features. zora river for example, a linear path for sure, but it could have been much more bland than what it was. it had high parts, low parts, secrets, spatial puzzles. if the entire land had such a living perplex world with such puzzles and such, it would be an unbeatable game. hyrule feild, in comparison, was fairly flat without many interesting landscape features on the whole)