Global search while nice, is not absolutely necessarily.
Shift Click an existing item to search? I don't want to search for the item I already have.
Minimum value is required since you are putting up a deposit on it. For the calculations, you cannot have a null or zero value.
Frankly, I like the GTN the way it is now. what we need is another way for crafters to easily provide a vendor to their guild at least. I foresee this as a separate GTN, much like Nar Shadaa, that would be placed on a guild capital ship. Wishful thinking, but I think it would be the best implementation and the most easily done.