My two cents worth.
For every person that completes the guide without error there is next to no feedback from them because, why would there? On the other hand for every person that does have difficulties it is because of a misunderstanding of the description or the steps leading up to that process, everytime that happens the guide is examined and a revision of the wording is looked at. However, more often than not the wording is clear and the reader assumed something. Can the guide fix that? Maybe, and the STEP authors endeavour to do so.
STEP is a fluid guide, meaning it is always in a state of change which means new steps may need to examined in the light of previous ones and also how it reflects on later ones. Which brings us to videos. Everytime a new mod is included the whole section would need to be updated to reflect the change in order otherwise users will flood the forum with: "where does this go, the video doesn't mention it!" The steps involved with maintaining a working complete video guide would overwhelm the maintenance of the guide itself.
Then there is the thought that every detail needs to be outlined. Yes and no. Most steps involving mod installation are the same for numerous mods so once the user has done the first, the steps are repeated for similar mods. Where there is divergence from the standard, STEP provides notes and detailed instruction to reflect that, or it tries to.
Lastly the comments about length of time to complete. You will usually find that those that say it doesn't take too long are like @Greg that already have most of the mods downloaded. This is far and away the most time-consuming part of installation. After the downloads are sought, the steps to install again are significantly shorter.
Am I trying to dismiss user feedback about the complexity of the guide? No, simply highlighting the points that some slip up on are often not due to wording or instructions, but a sense of being overwhelmed with content. All feedback is appreciated and examined for action.