Because I'm starting to feel the need to do so, even a little bit.
- Why Isshin's so enthusiastic about his family (and, on top of that, why he keeps adopting people)
- Why Isshin A) never told Ichigo and the twins about being a shinigami and B) continues to keep them in the dark about it
- How Isshin feels about all the shinigami from his world in camp and, in a similar vein, all the people from his world in general in camp
- ...um, I dunno. Anything you want to know about, feel free to suggest!
I was going to add "why Isshin's so nice to the Nobodies in camp" but then I realized that it's not really essay-worthy: he just thinks it would be hypocritical to treat them as something monstrous when he treats his own son as human.