The berserker lord occasionally suffers from mediocre defence, but only really in that you have to a bit more careful about using it as a blocker than with the king. While it takes attrition, -/17 with inspiring is a pretty good nerve value, so it can absorb a lot of hits. True, there are units that can stack up that damage quickly, but there are also units that can easily punch through a kings Def 6+, and as an individual, particularly a movement 8 one, it isn't too hard to avoid the worst units. As I said, something to be aware of but not a major weakness.
I use most of the individuals in the list myself depending on what other units I have, with the exception of the Warsmith, since cannons have been crowded out of my roster by all the other things I want to include. Most commonly, I end up with one each of King, Berserker Lord, Stone Priest, and Ranger Captain.
The King and Berserker lord are both good support models, but I've always felt that the wings are too many points on a hero best used in support of other, non-flying, units. My berserker lord is also sometimes on foot to save points, and because I really like that model. I like to haver one of each, but if I'm not bringing berserkers I find it hard to justify a berserker lord over a second king.
The Stone Priest is a brilliant support caster, with Surge on elementals giving my army a vital edge in close quarters manouvering, and Bane chant giving the units that need it an edge. Bane Chant is also particularly good with a lot of the units I use that have lots of attacks but limited CS, most notably Flame Belchers, Rangers and Berserkers. I've also found rangers work best in pairs of regiments with a Captain along to provide relatively cheap vanguarding inspiring, while Herneas for additional cost also provides reliable wounds at range or melee.