AFAIK level scaling happens on loading the map. You could enter the sepulchers then leave- come back when you're a higher level. Changing difficulty while in the loaded area won't change the encounters. 

 

I haven't had any issues once I reach level 10+ with enemies that are 3 levels ahead of me.

 

I will say that the change to agro (bug? glitch? gameplay feature?) does make the battles significantly more difficult. I'm cool with that, as I like a good challenge- but I can see why it would be frustrating to others. 

Perhaps this is a result of turning off level scaling?

Level scaling scales the enemies level up/down by four levels.

 

I.E. A level 2 character runs into a level 14 enemy, the enemies level changes to level 10. Likewise, if a level 14 character runs into a level 2 enemy, the enemy scales up to level 6. 

 

When I originally did hanging sepulchers I was able to stealth around, grab each skelly individually and gank them. Now you can't really do that without attracting all their skelly friends. 

The difficulty spikes are much different in this game than in the last. I suppose it does have something to do with the more open nature. In a way that's cool, but it can be a bit of a drag when you're cruising along and suddenly every foe around you makes you feel weak.

 

Having said that, I did have an easier time of hanging sepulchers when I took the side route instead of the main one. It was a little easier to pick off lone skeletons once I made it past the first big group.

 

Don't forget to look at your weapons too, and make sure you're dealing the right type of damage for enemies in that area.