My current OOO run is level 4 and is swimming with more septims than he knows what to do with. In one case, I was stumped by an enemy boss (Goblin Jim) not because he was tough and I needed my wits to survive, but because he kept healing himself. And he had more magicka regen than I had attack power. Even with witsplinter, a knife I looted off the women's gang in Anvil which does damage to it directly. To kill him, I had to run around a high cliff and hope he tripped and fell. It was actually really boring.
On the other hand, the AI remained stupid, so I was able to lure a Sylvan Ranger (who, actually, I hadn't meant to find - he just started chasing me mindlessly across the entire world) to just outside Kvatch, where I ran in circles while shopkeepers pummelled him to death with fists (the Imperial Guards were there, too, but I think they must have hit eachother by accident or something, because they fought instead - which still worked out fine for me). His loot - a healthy collection of Elven Arrows which I immediately sold to one of my saviours for all of her money, and a pile of heavy armour. Unfortunately, I'm using a light armour-wearer, so I had to sell it all. In fact, there was more loot than I could carry. I left a lot of it on the road.
I do like OOO, don't get me wrong. It's entertaining being locked in battle with highwaymen for several minutes, with nothing but my block skill and a pile of "Restore Health" potions between me and death. But there was so much focus on the "Haha, let's make bosses super tough so people have to come back later, haha!" that many of them are of equal difficulty to their vanilla incarnations, except for the boss at the end, who is of variable strength regardless of his location in the world, forcing you to walk back through the empty dungeon virtually empty-handed for your efforts. After you savescum during the trial and error phase. The exceptions to this seem to be Amazons and Sylvan Rangers. Who hang out outside their dungeon and chase you over the worldmap for all eternity.