When I added friendly monsters and Wolf3D dogs to Doom, I tweaked the randomness to make the dog behavior more life-like.
Friendly monsters go after enemy targets, but absent any targets, they follow you in semi-random motions, but they stay a comfortable distance away from you, except when getting onto a platform or other crowded space.
Also, demo reproduction was a huge issue. We had to do all kinds of versioning to make sure that a demo which was recorded with one version of Doom/Boom/MBF/etc. was faithfully replayed with the current version. One tiny mistake, and the whole demo could go into a tailspin. This sometimes meant we had to preserve bugs like Lost Soul stuck-in-wall bugs.
Oh, and randomness could have fixed the monster-stuck-in-doorjam bug, which is easily reproduced in E2M4 with the Baron by the blue key. The code assumed that if a monster was "in" a door sector and was blocked, then the door simply needed to be opened, and then the monster could continue in its current direction. Better would be to rotate the monster's direction randomly to help them to get out of the sticky situation. That was our fix in Boom.
Friendly monsters go after enemy targets, but absent any targets, they follow you in semi-random motions, but they stay a comfortable distance away from you, except when getting onto a platform or other crowded space.
Disclaimer: I'm the author of MBF.