Second, it's, you know, Japanese. That's the real challenge of the thing. Our hiragana comprehension is fine, but we don't exactly have a large enough vocabulary to be able to build words from randomly-selected characters. Honestly, at a reduced Wii Ware price, we'd be tempted to jump on this like we wanted to for the PS2, PSP, and DS versions. Of course, there's no chance at all that Namco Bandai will allow that to happen.
If you think Mojipittan is cute, check the official Mojipittan site for wallpapers and MP3's from the other games, and try your hand at the demo version!