Everyone plays this game better then me on nightmare. Hard is my best difficulty and even then I suck, i never go without companions. Anywhere.
Admittedly, I tinkered with this ONE build (other than you, I'm too dense to focus on more than one single character) for ages, and turned it into a complete joke.
At this point, I have virtually no cooldowns (with Opportunity Knocks, a single Leaping Shot refills all active cooldowns, hilariously including its own), and a 30% chance (Griffon Bow) to trigger five Hidden Blades with every basic attack.
I really only soloed a dragon, which still took some time, to see if I could do it at all. I never go without companions anywhere, too, because why wouldn't I in a BW game? I love them!