John Romero explained why there was a difference in movement speeds.
Doom‘s one of the best ambiance elements were the speed of Doomguy throughout the game. Quake, on the other hand, reduced the speed significantly, although the appearance of 3D made things still revolutionary. Why were we slower then? Romero, one of the former iconic characters of id Software (he left to create Daikatana, which flopped…), explained in a blog post why there was a difference.
Quakeguy was slower simply because the levels were smaller, as they had to be under 1.44 MB (3.5″ floppy disk, anyone?) in size. There was a compensation to be done: the slower speed made players feel the levels were bigger than what they actually were.
If you are interested how the vanilla Quake level editor looks like, read that post – let’s just say that a hobby developer with id Tech 1 has an easier job than id Software over two decades ago…