1: It could be that the height of the space was actually detracting from the visual impact of the tree itself.

II: It could also be that your professor wants to challenge you by throwing you curveballs - remember, the final product of school is not the buildings you design, it's the designer you become.

C: Maybe your professor just didn't like it. Sometimes that happens, and you'll typically be better off if you accept it as a challenging new design constraint. 

Good luck!

Aesthetically speaking, the internal use adjacencies and circulation necessitates that urgent considerations be made of the anticipated degree of human ambiance.

On the other hand, the massing of major elements presents extremely synergistic challenges to the philosophy of commonality and standardization.

Required reading: On Bullshit, by Harry G. Frankfurt.

A transition between two spaces that is too extreme can make two spaces feel disjointed.  An impressive compression-expansion transition needs to be just varied enough to be noticed, but not so different that they can't be compared to each other.

I would highly recommend reading the book 101 Things I Learned in Architecture School by Matthew Frederick.  It's a quick, cheap read and it will help a lot with understanding many of these sort of architectural/spacial tricks.

"Too much" is a rare criticism unless your professor means "too many things going on at once."

Architecture is often about taking one idea, one "move" and making the entire building or piece about that while letting other elements fade into the background. 

I don't know what your work looks like, so I cannot comment specifically on it,.

You NEED to learn this...

Thanks everyone! I fell a little more prepared to go into studio tonight. Not exactly sure what my solution will be yet, but I am at least approaching my work a little less bitter! I think that my problem was that my spaces weren't flowing well together. I will definitely check out "On Bullshit" sometime :)

And actually, CultureofCon, I have been reading 101 Things! Picked it up at the Met in New York when I visited. Good to know that someone else recommends it because I really enjoy referencing it, it's concise and seems to have a lot of good stuff to say. 

Maybe your professor is trying to get you to think a bit deeper about an overlook means. Not very well, of course, but.. 

Personally when I think about the best place to experience a tree, it would be underneath the canopy looking up, not looking over it. Overlooking's a little too conquer-y for me.

You want to capture the size and magnificence of a large tree. How can you do that if you are building a structure that looks OVER the tree? 'hey, look at that puny tree. this man made structure is MUCH more impressive!' 

Meanwhile, how can you ensure people are actually looking at the object they are supposed to look at? After all... a viewing platform overtop of a tree would also give broad vistas of the environment around it. 

Anytime you have to climb something, the space automatically becomes compressed because you are focusing on your own self and the moves that your own body makes, especially if you are climbing high up. Once you can stop focusing on your body and switch this focus to the tree and the height you're at, that would give you a feeling of expansiveness. So in my opinion, a third 'compressive' space directly between climbing and viewing is superfluous and may even ruin the experience. 

I'd cut down the tree and use the wood to make chiase lounges on which to recline and contemplate the space formerly occupied by the tree.