Things such as short swords and daggers are commonly used as offhand weapons in conjunction with swords, and it wouldn't be hard to learn to use another as a main weapon rather than a sword. But a longsword would indeed be much harder, though possible. However, a claymore in each hand is right out, unless you're a Kran. Maybe a Ynnwn. Maybe. But two-handed weapons I believe are coming, though perhaps a mode for longswords to either do one-handed or two handed. One handed would allow a shield, but attack slower and with less strength. Two handed would have no shield, maybe a bit of a shield bonus, though less than a shield would give. But two handed would also attack faster and stronger.