I think the creators might be sending a welcome message here; any girls watching the show should be paying attention.
To Heart: Akari
Shingu: Nayuta
Jokes aside, To Heart and Shingu leave the same sort of warm impression although their genesis, plot, and other attributes are drastically different. In one case it's all about shagging your classmates, and in the other case it's about the fate of the world, and yet...