You can change the difficulty during the game. The combat you encounter before getting to Cyseal is meant to be a tutorial, so the fact that it is easy shouldn't necessarily provoke an increase in difficulty; see how you do after leaving Cyseal (north west being the easiest gate to leave by).
Depending on your character builds and tactics, hard is arguably not very hard. Harder difficulty modes are planned for a future update, including changes to opponents, etc.
