No, it was in fact quite balanced. The reason no one took that "build" seriously is because it required you to never ever miss an attack, because the way it was originally written, the action in question triggered another attempt to attack for each time you hit.
This was addressed with errata almost immediately when they realized that it was possible to get very high hit bonuses, making it so you might go many attacks before missing. IIRC, it was still impossible to guarantee that you'd hit, so it would terminate eventually, just not soon enough to do an appropriate amount of damage.
I would also like to remind you that "doing nigh-infinite damage on a single attack" is by far the LEAST broken thing you can do in D&D 3e. Natural Spell, all by itself, is more broken than an entire high-level-epic Ranger build focused completely on cheesing one single power the one time you can use it per day (as, IIRC, this was a daily power.) And the insane power of Natural Spell was never addressed.
But I will say, I at least appreciate that you are complaining about actual issues 4e had, instead of ones it never had. I've seen far too much of the latter.