I'm at level 15 doing all kinds of side quests. Here is my early-middle game experience.
One thing I noticed is that pulling is not working very well on 3.1. Once a enemy turns hostile, the whole mob (and their brothers) run to you aggressively. And they seem more aggressively targeting your backend members (not 100% sure). I didn't notice any attribute or ability buffs. So once you're prepared to face the whole enemy band, it's about the same. At least the early bosses are not tougher -- I still can kill Uamoru the Pretender and get Aamiina's Legacy at level 12. Like the previous posts pointed out, once I figured out the order to take out dangerous enemies, it's a lot easier to control the situation. Luckily, I have an assassin to do just that.
Although this ruined my fun to see how many enemies my archer can take out single-handed at the beginning of fights, I like this change. This feels more like team fight where each member can play an important role.