There's nothing more important than the gameplay formula the Williamses invented...
Whaaaaaaaa? I mean, I love Kings Quest, but you are fucking bonkers on so many levels here.
At the most basic level: after roughly 87/88 Sierra succeeded in large part in spite of Ken Williams, not because of him.
Let's start from the beginning, then.
I have no idea who came up with the gameplay formula we've seen inside Sierra games. I said the Williams did because they founded the company, that must come with some bonus, no? But who cares who did it, as long as we acknowledge Sierra On-line designed their own games as they were.
The particle of god in a Sierra game is a situation, not even a real puzzle, but an "open problem" that can be solved in different ways, and it has consequences everywhere, deep and permanent.
It's at the same time a defined and open formula! It allows police simulations, crime stories, medieval stories, roleplaying games, each different, each even allowing manuals for following procedures and historical informations you need in the game. It's an amazing design structure, imo, one that's open to be adapted into many genres. Infact an "adventure" is a generic term, adaptable to everything. That's the reason why Sierra games could be the mother of all videogames, because they were "real" adventures, hell they even had a score that looked like arcade games! This freedom of choice undeniably comes from D&D and tabletop board games, freedom in a made up story. Sierra designers were kids who played D&D, like everyone. Sierra kids used this formula ever since their first titles in the 80's, carried this torch up to the great 90's masterpieces, and now Hero-U revived it, stripping it of its more punishing consequences, ofc.
Now, many other game gurus like R. Garriott, W. Spector, and Black Isle, maybe designed their games not taking inspiration from Sierra games, especially Garriott who started creating games around the 80's too, but, like Sierra designers did, by directly playing D&D, interpreting and converting it into a videogame.
But isn't the idea of multiple endings a little too specific to not be an original and unique invention they borrowed from Sierra games, which undeniably were the first one featuring the idea (unless Infocom's Zork did it before)?
Also, since nobody today seems to really GET choices & consequences, and all we see is ridiculous Bioware style ethical dialogues and romance, isn't Sierra legacy the most important thing in videogaming today? So Hero-U should be a lesson for all. Is there even non linearity and freedom of action in Wasteland 2, Pillars of eternity and such?