(re: QfG4 – Collection version vs. standalone) I can’t say specifically for QfG4 because my used copy didn’t come with a manual, but in general I’d say yes, the original manuals are way cooler than the ones in the collections.
For example, King’s Quest 4 had a little storybook that gave the history of Daventry and what had happened in the previous 3 games, leading up to the 4th. The copy protection for that game required you to look up a specific word on a specific page in the storybook. In the KQ collections, only a list of words (the “answers”) were provided, so you could get past the copy protection. The storybook itself and the history of Daventry are not included.
Even if much of the info is included (as it is for the KQ6 manual), the original manual itself had nicer materials, cool binding, etc.
I expect it’s the same for all of the collections. I do have the original manual for QfG1 but I have not looked closely at the Collection manual to see how they compare.