I don't think they need anything that's gonna beef them up against any classes other than rangers/warriors/necros/battlemages but the last one is a maybe.
How to fix Zerks
you don't rage until he's almost dead or you're almost dead anyway.
You don't rage unless you are losing by a little. If you're losing by alot, run. If you're winning by alot, lag them.
Certain berserker skills have high chances of success while the berserker is enraged, experiment and find out.
giving zerks fourth attack would be like giving bladesmasters the ability to be proficent in all the weapons in the game. Totally unfair.
Well it's not THAT bad. Giving BLMs all weapons is a completely different ballpark. 
But I agree that they don't need anything other than a good player to play one properly. I seem to remember Bazin (Dwarf Zerk, played by Mindflayer I think) and Behren's Human Zerk doing pretty good. IMO they just seem to get less attention than other classes, which is a shame IMO as they're one of the most fun classes.
Dey
Does anyone remember borroc, he pwned plenty of people. and that was before they got paths. Let guu get her hands on another ogre avatar zerker, you people would be complaining that zerkers are overpowered. Well, at least I think most would. Most classes have many things that would make them in many peoples eyes more balanced, or powerful, but they don't have it because it is supposed to be a challenged to play that race/class. If everything was uber the game would get very dull, very quick. Plus the imms would be trying to drastically change each class and such to balance against everything else, it would get ridiculous.
Zerks are challenging because there is no room for mistakes. Battles are hard and fast, and you have to make every move count because of that. With Collkin, I didn't have a single fight that dragged on and on. You'd be straight in there, someone would flee, a little bit of chasing, and then someone would be going home in an ambulance. Makes Zerks among, if not the most, fun class in FL IMO.
With a class like a cleric, you can often afford to make the odd few mistakes because you can flee and heal. Zerks have raw offensive power at the cost of defensive power, and their only form of attrition at all is to catch ticks thanks to regeneration.
Zerks die a lot because of this. They can absolutely be beasts, but unless you're a good PKer, I'd argue that you'd die more with a Zerk than any other class.
Just my opinion from a limited time at pinn with one anyway. I'll admit that by going Undead, I did NOT do myself any favours, simply because I was not aware of one of Undead 'traits' shall we say. So maybe my view differs from that of a regular Zerk, because I had to adapt my battles accordingly.
Dey
Don't make me roll up a zerker to put this thread to rest!
Do it. Your last one was awesome. 
Dey
I always thought that roar should affect everyone your in battle with.
AKA:
You are fighting mob A) and mob 
You are targeting mob A)
You roar.
Mob A) and are now affected by the negative effects of roar
OR, possible roar could have another effect, like scaring your opponents into dropping their weapon/shield. As it currently stands, roar isn't too great.
Or at least make roar automatic when your raging with path of devastation
Also, I always thought path of devastation should make it so you can weapon/shield cleave all weapons/shields, no protections from it.
Since the helpfile talks about how it can break even the strongest hardened steel or something like that.
Path of devastation has another useful effect that is often overlooked; since I've seen a lot of people talking about how the hit/dam boost is the same for different paths.
And I do believe I know what it is. And it makes that particular path very cool. If you're not too scared to pick that path, that is, and go anger/fury. 
Dey
I like some of your ideas Mudder
There is more to damage than damroll. And Devastation surely gets more.
Few things can stop a ogre berserker devastation wielding a polearm.
The damage that he will output will be insane, and he can defend "well" vs meale. And what he cannot defend he can ignore 
.
Roar can drop weapons/shields, quaff a detect magic and look at the effects.
Of course only a healer would drop sutch a shield. 
I was thinking more like a certain shaman spell.
Except not be affected by dirt/blind because its not visual, but audio.
Don't make me roll up a zerker to put this thread to rest!
Who was your last one?
http://www.forum.forsakenlands.org/showthread.php?t=1680
I took tons of beating from him. I was a huge fan of Bazin, on both the PK and RP fronts.
Dey
I always liked the fury path because of the ladder skill they get because of it. It makes Polearms and even axes way more fun to walk around with double gripped.
Ooh, another idea. Roar could also give a random "fear" like effect. Since if you roar like a champ, it'd scare the hell outta the guy your fighting.