If they did remake The Land Before Time, only thing I would hope that Universal would do is put Zack Snyder in the director's seat. He was the director of the remake of Dawn of the Dead, and it is the second highest grossing zombie made made (used to be the highest until Zombieland, which I found boring compared to Dawn of the Dead), and considered one of the best.
In short, if Zack Snyder directed the remake, that would be the main reason for me to watch it (especially after watching Dawn of the Dead and The Owls of Ga'Hoole: Legend of the Guardians, both directed by him), I would have a feeling a remake would be better if I see his name attached in anyway.
I don't think anyone can make this better than Don Bluth.
For the reason I explained with Dawn of the Dead's remake above, I'm sure that Zack Snyder could make a remake of The Land Before Time better than the original than most film directors or screenplay writers could.
Remake must be in traditional animation and not computer. (I really dislike computer animations).
Zack Snyder could make computer animation work as long as it is as realistic as Happy Feet (One or Two) or The Owls of Ga'Hoole: Legend of the Guardians, all made by the same, or similiar, studios, and they are more visually appealing than anything could be done in traditional. All three were praised for their animation style.
Even if it was done at the computer animation style of Blue Sky Studios and 20th Century Fox (creators of the Ice Age movies and Rio), then it would look good in computer animation then too (example of 20th Century Fox/Blue Sky Studios animation in my signature image).