Hiroki:
[spoiler]The Hollow's merger with Rukia was something far less permanent than say, Metastacia with Kaien. Which is an event entirely likely to be the cause of Ichigo's powers as a Vizard, remember what Ichigo said at the end of the movie? Even if their memories vanish, their bond stays. Kaien's memories might be with Aaroniero, who absorbed Metastacia, but the heart remains somewhere else. Ichigo feels like he and Rukia might have met before their first meeting. Ichigo's Hollow powers influencing Orihime and Chad long before Urahara's Shattered Shaft trial confirm as much.
When Ichigo tried to recover her Shinigami powers, he did so to completely remove any trace of Hollow within her. You can even tell he specifically avoided use of his own Hollow's power; he used his own reiatsu instead of the Hollow's black reiatsu. Considering this Hollow was a fairly weak one, and not specifically designed for the purpose of Hollowfication, I doubt it left any lasting impression on Rukia.[/spoiler]