What was the role of women in Germany in the years leading up to WWI? Specifically from the Industrial Revolution and years post-unification? What was the class/caste system?
The most radical labor unions, including those with ties to communist and socialist organizations, often featured women among their leaders. Part of this may be due to inequalities, especially when realities didn't meet the rising expectations several people have mentioned in this thread. Clara Zetkin, mentioned above, is a great example, but perhaps the most famous female radical was Rosa Luxembourg, who led opposition to the war and was assassinated by Freikorps members after it. I have linked to a translation of one of her most famous written works, The Accumulation of Capital. It nicely elucidates her views on capitalism, including its effects on women, and includes some scathing critiques of pre WWI German society.
Class dictated the kind of roles that women were expected to follow, as with many other European countries. The poor would be expected to work in factories in degrading and often dangerous positions. However middle class women were expected to not work and to be a homemaker, raising children and running a home whilst caring for their husbands. Class, as so often was the case, dictated the kind of lives and opportunities that you could expect as a woman.
One thing that German women experienced before World War I was enthusiasm for German colonization. Colonization opened new employment opportunities for German outside the typical European and English women's occupations of nursing and teaching. There were even colonist women farmers who wrote diaries of their experiences that were eagerly embraced by a readership in Germany. For more on this, see German Women for Empire, 1884-1945, by Lora Wildenthal.
Class was a very strong factor in determining the roles of women. Wealthier women often lived very privileged lives; poor women obviously did not. Women were not allowed to vote in Germany until after World War I, and so they had only a limited and indirect influence on the political situation. It might be helpful to you to do some research on Clara Zetkin, who was deeply involved in the feminist movement in German in the period you're interested in. Search for information about her will probably help you find much other relevant information. Here's a link that may help:
Women did work sometimes, as Germany became more industrialized. It was not uncommon for poor women to work in factories or as labor in shops. Middle class women, on the other hand, would be expected to be homemakers. They would not work, because it would be considered beneath station.
German women were not really all that different from other European women of the time. This was a time during which expectations placed on women were increasing. The rise of the middle class made it so that women were expected to fit into the "cult of middle class domesticity" in which they made their homes into perfect places for their husbands to relax and in which they raised their children to be well-educated and well-behaved. At the same time, there was not enough in the way of labor-saving devices and such to really give most of them the time to do all of these things. This led to increased stress on women during this time period.