I'm going pretty slow with this game, (about 4 hours in at level 15 or so), but I haven't come across any difficulty spikes. I did do one free battle that was pretty tough, and I was about to die so I retreated. The story battles have all been pretty easy though.
I'm enjoying the game, but so far I like the story and characters in DS1 a lot more. Maybe it's because this feels like too much of a repeat, while DS1 was something new. I dunno.