I've always considered myself to have a kind of 2D complex, but I don't think there's anything inherently unhealthy about it. Though I guess that kind of love is guaranteed to be unrequited, and for some that's bad, for others that's good. Don't have to think "should I ask them out", because you can't talk with them. For that reason it reduces the pressure.

I do think it will pass though. More than likely you'll find another character.

As for me, I had a whole year crush on Haruhi and then Yuki, but lately I think I'm favouring Sasaki more.

That being said, lately I've been feeling my first crush on a real person in nearly four years. Whether I actually do something about it is another matter entirely. Rather than risking disappointment I might just enjoy the change in preferences for a while.