I'll concede the point, except that you're leaving out, I think, the most striking similarity, which is that the Romulan time travel results in a Kirk who is somewhat of a loser/delinquent (although perhaps in differing degrees), and who ends up serving on an alternate-history Enterprise in a very low rank.Besides, it seems to me that the only common element between Killing Time and STJJ is that they both involve Romulans going back in time to change history. But the nature of the historical change, its degree of success, and the time frame in which it unfolds are completely different, as is everything else.