I felt the second is more difficult especially in the starting hours until you get better kit and money for spells. I started on classic but bumped it down to explorer.
It's because of the new physical/magical armor system, really. In the first game you could knock down half the enemy group or set them on fire before combat even started. Now armor prevents the shenanigans until you break it down completely. And the AI is sneaky and evil, too. From what I could tell you really want at least one character with a bow or xbow to destroy physical armor if you want to use the warfare skills effectively. On the other hand, this also makes a summoner pretty valuable, because 3 elemental totems + incarnate does a number on enemy magic shields