Personally I don't understand why you would want Lone Wolf.
While you undoubtedly get more AP's with companions, the AP's you get with Lone Wolf are more buffed. The real effectiveness of this depends on your build/class though.
There are many more factors in play as well. Unique items can only be on one character for example, so if such a unique item would be significantly more powerful than all the other items, it could pay off to make the most out of it on a Lone Wolf. Same with potential stat boost potions etc...
To me personally it also heavily boils down to simply not liking the companions all that much. I would like to build them from the ground up instead of having wasted stats.
For me the game works fine with just 2 companions, I kinda like the focus on their duo interactions. And if it adds extra challenge; bring it on
