That's what I've been saying. I definitely think Clark overall (not strictly combat, but just general hero-ing) is a step above the rest, both on the page and metatextually, but any one of them should be capable of taking down any of the others. And in fact, most of them have beaten most the others at one point or another.
Except, as you say, Bruce, who doesn't have the juice to win a fight without spending a lot of time setting traps and circumstances that'll allow him to control the way things play out. I don't worship the Batgod and his divine prep time, but I'll freely admit the guy is smart and resourceful enough to successfully get the drop on the other Leaguers if he plays his cards right. Which, I think, is fair given that any of them, if you drop them into a cage with Bruce unexpectedly, would tear him to pieces with minimal effort.
That's happened a few times that I can recall.
Another drawback is that Zee, depending on the writer, gets hooked on her own hexes, like an addiction. It's not really a limitation or weakness in the traditional sense, but it's screwed with her in the past and has gotten in the way of her doing the job.
But generally, her power doesn't seem to have a legit upper limit; it's just whatever she's capable of saying clearly and concisely, and the fact that she can be completely nullified with some duct tape. I count her among the reality warpers, and she's maybe the most powerful being on earth who isn't jacked up by ancient magic helmets or godly blessings.
Can anyone think of a character more powerful than Zee, who doesn't rely on some outside power source?
"We all know the truth: more connects us than separates us. But in times of crisis the wise build bridges, while the foolish build barriers. We must find a way to look after one another, as if we were one single tribe."
~ Black Panther.