D&D General Structural Flaw of the D&D Combat System

[Willie the Duck]

I am not sure it was designed as a dungeon crawler. It was a wargame at the level of individual units and the first adventures were dungeon crawlers, but that changed with Tracy Hickman at the latest, still during the 1e days.

It supported dungeon crawling, but I am not sure that was the design focus. I am not even sure I would call 1e designed. To me 3e was the first actually designed version, the ones before were organically evolved / mutated / hacked together more than designed.

1e had so much... cruft and weirdness in it that it was easy to miss the dungeon-crawl pieces.
I think if you started with B/X, it was hard not to see the Dungeon-crawling front and center.