Yes, they can solo well, as long as you have a few key stats.
- Crushing Blow. Absolutely vital for a Barb playing in Hell, making each attack just like static field. A double swing or frenzy barb with low damage but decent CB is still going to plow through enemies. Hell, there are plenty of 'builds' out there that rely solely upon CB for the majority of the damage. Yes, it is that powerful.
- Deadly Strike/ Open Wounds. Less vital than CB, but both are still very nice in taking chunks of health out of enemies, even with low damage weapons. With the combination of CB/DS/OW, you will see a huge difference in killing speed. I don't recommend going to hell mode until you have some sort of combination of the above.
- Slow Target. Even less vital than the above, but slow target is going to keep your Barb alive much longer than normal. This really helps when tanking packs of frenzytaurs in A5 hell. High defense and physical resistance only goes so far.
As long as you have the above, just follow 'typical' melee rules - high defense, decent life steal, increased attack speed, and so on - and your Barb will do just fine in any part of the game.
As for Iron Maiden, it is not as big of a deal as many claim it to be. Simply walk back a screen or so, and all the melee enemies will follow you. Deal with them as you normally do, and then walk back to the remaining 2 or 3 caster knights, and pick them off. It doesn't matter what attack you have to resort to, picking off a single oblivion knight does not take a long time, even with your bare fists. Yes, it is a tad bit slower than a chain lightning sorc that just spams the whole knight pack, but at the same time, you don't have to fight EVERY single one of them with beserk as many people will have you believe. Divide and conquer, so to speak.