It feels like it is an incredibly short game that gets people to feel like the game is longer by making you go through the same area dozens of times.
There is a grinding element. The thing is even when you're killing the same enemies over and over, it's still challenging, and you are being rewarded with something worthwhile for your character progression. Plus you're developing your playing skills. So it's essentially practice, and you're only forced to do it because you need it - either your character is too weak or your skills are. When you and your character are good enough, you can get through an area the first time and don't have to fight the same enemies over and over.
Plus, DS2 seems incredibly long to me. Lots of areas already and I'm not sure how much more there is. I'd actually have preferred it to end already so I can move on to DS3.