What is unleavened bread? What is the purpose of the "bread of affliction"? How might the texture of the bread relate to the underlying purpose?
Rabbi Moshe Isserles, the leading Polish Ashkenazic authority of his time, explained that the mysterious bread referred to dry crackers. According to this opinion, cracker-like bread is not fully bread for the purpose of blessings. Why not? What about matzo?
Rabbi Hershel Schachter (Hand Written Teshuva to Rabbi Meir G. Rabi)
There is no custom that restricts Ashkenasim from eating soft Matza. Although Ashkenasim have eaten hard Matza for many years, such a practice has the same significance as the practice of making the Parochet of blue material rather than of red or maroon material. Besides, there is evidence from the Mishna Berura that "Matza made as soft as a sponge" can be used for the Mitzvah of eating Matza. Furthermore, the Rema who mentions that Matza should be made as Rekikin, means to say that Matza should be made thin, even less than an Etzba (about 12mm), not one Tefach thick (about 8cm) as permitted by the Mechaber. He does not mean that Matza should be made as thin nor as hard, as wafers.