While the question was on hold, I added the following addendum edit hoping that it would make my intent more clear "EDIT: I'm finding it difficult to understand why this question has been put "on-hold" as being opinion based. I'm not asking if it's a good idea or if it makes sense. I'm simply asking if there is any reason within canon that Worf could not have attacked the Enterprise during the alternate timeline of Yesterday's Enterprise or if anybody has any inside knowledge of the thinking of the writers."
How is this opinion based?
Addendum edit to the original question, Posted 9:40pm EST 1/2/14
FURTHER EDIT - NEW
TO: Rick Berman
FROM: Michael Piller
DATE: Oct 3, 1989
Re: The Time Travel Story “Old Enterprise” by Trent Ganino…what about this as a twist… we’re in this routine action story when in flies this old Enterprise through a time warp, however we choose, and immediately, things change without anyone on board realizing it. Picard is still in command..Riker, number one Data in position, but Worf is gone (in fact a member of an enemy crew) and Tasha Yar is at security…
The above is a quote from The Making of Yesterday’s Enterprise by Eric Stillwell
The question of the possibility Worf's involvement in this episode as it relates to Khitomer is uninteresting and circular. As evidenced by the memo quoted above, at least at one point the possibility played in the minds of the series creators. As an answer to this question I would like to know why the creators chose not to use Worf in that way, or if there is a reason within canon that I am missing. Because the Khitomer Massacre happened (in our timeline) long after the events on Nerendra III, it's irrelevant to this conversation.
As written, this question is answerable. As a matter of fact, having found the memo quoted above, I might very well be able to answer this question myself eventually, if the question were reopened.