Hand of Evil said:...it is even possible that Hiro is his own forefather...
I get the notion of Hiro singing "I'm my own grandpa."
Hiro does go through some experiences that turn him into the character we see in the subway, talking to Patrelli. This includes, but is not limited to, fighting a hungry t-Rex, armed with a a sword. I mean Hiro has the sword, not the T-Rex.
I don't find the Nikki story arc dull, i just find Ari's performance generally lack luster.