As I said, in a way, that's how I experienced it. Not that it's exactly the same.
We could extrapolate a scenario where this would be the case: let's pretend that attack, disarm, sunder, grapple and trip are all equal to each other for class X used under the right circumstances, which happen in a way always giving me "fair" opportunities to use them.
Class Y has only Attack. But it's 25 % better then my attack and can also be used under all circumstances.
I think you are recalling the two problems D&D has typically suffered.
* Specialization far outweighs diversity.
* Diversity just means you have more ways to suck.
In your case, you have a fighter who was capable in a variety of corner-case scenarios: A foe with a superior weapon, a foe who relies on grappling, a foe who is standing in a strategically poor place, etc. (In fact, only trip is universally useful, since most foes must stand to attack. This merely proves how Imp Trip was an annoying, if superior, tactic for shutting down most foes).
You are competing with a single-minded ally: she doesn't have as much diversity, but my god can she lay down the smack. In theory, you should be equal (diversity = narrow focus), in reality, when all you have is a hammer, everything looks like a nail. Sure, you might win a grapple against a giant, but the other fighter can just full-attack it and kill it. Ditto with sunder, bull-rush, disarm, etc. (Again, excluding the cheese-fest that is trip for a moment).
In theory, a bard is the most powerful character class: it can heal, deal sonic damage, fight with some skill, and use a variety of rogue skills. In practice...
So unless you fight a lot of foes requiring grapple, disarm, and bull-rush, those tactics < full attack with a +2 to hit, +4 damage. D&D rewards specialization of task so much that jack-of-all-trade classes (monk, bard) tend to fall short by not being good at anything. The same holds true for sorcerers who don't optimize spell selection or rogues who spread their skill points over too many skills, or fighters not focusing on a single weapon.