TL;DR: Switch to OpenGL to fix slow walking speed.

So I solved my own problem before I got a chance to ask a question here but I thought I would post it anyway in case others have the same problem. I was running the game in DirectX mode and the walking speed was killing me--my character moved and attacked at a snail's pace. I scrounged around for a solution on google and someone had suggested switching to OpenGL, which, sure enough, solves the problem.

EDIT: This applies to E1, I have not played E2 yet.

This DirectX vs OpenGL all boils down to what hardware and drivers you have. I, for instance, cannot use OpenGL else I get the symptoms (particularly blurry text) other people are saying they get with DirectX. So if you get blurry text, slow downs or other funkiness on DirectX, switch to OpenGL, and vice versa.

It's still really slow. I guess it's more of a style thing?

It is, indeed. One of the mayor improvements of Book 2 was to increase the walking speed of your character. I've just started re-playing Book 1 after many years and have to say the speed doesn't bother me much though. It was worse in my memory ;-)

I asked Basilisk about it and they said they wanted to emphasize the feel of exploration. And no, they aren't going to go back and fix the speed for Book 1. : (