Shavuot: What is the Torah?

Discussion of the format of the Torah today, split into the written and oral Torahs. What will be the Torah in the Messianic era? The Torah is capable of change, though it can be dangerous if you don't know the boundaries of what change is allowed. Does the Torah really change? How? Why? There's a beraisa which splits all of human history into 6000 years. The first 2000 are tohu, the next 2000 are Torah and the last 2000 are the Messianic era - and at the year 7000 the whole world will be destroyed and only the World to Come will be left. This leaves us with many questions. The world was meant to end after the giving of the Torah and Moshe was meant to be a Mashiach, but then Israel sinned with the Golden Calf. Why is Torah so critical to the existence of the world? The Torah is meant to correct the issue of nahama d'kisufa, the shame of the soul that it was given the World to Come without working to earn it first. The world was created only with the attribute of justice, but then the attribute of mercy was added. The world could not exist without mercy. What is greater, love or truth? G-d must hide the attribute of mercy from the attribute of justice, then it cannot function. Why is there so much suffering and darkness in the world? It exists to hide existence from truth. What's the idea between the two sheep sacrificed on Yom Kippur, one for life and one for Azazel? Why do we have an entire "storybook" as the first part of the Torah, instead of simply the parts that deal with the 613 mitzvos? What is a Jew? What is a Jew's power?