http://en.wikipedia.org/wiki/Japanese_honorifics#KunIt's never useful information if there's no cultural context. What does kun tell me? Jack shit.
A lot of foreign works require you to learn the culture. And this entire thread does it all the time even if you don't think you do. For normal name calling, there really isn't much issue. You expect parents to call their children without honorifics and such. But there are so many cases in manga where honorifics is a plot moment. Battle shounen readers might not see it often but it is important in other works. Senpai and kōhai are also not translatable but I find them important. It actually tells you who is the more experienced individual per context instead of figuring it out.
I'm not some adopt everything Japan weeaboo whatever. I'm simply willing to "learn" when it applies to reading works. And I know how honorifics work and it wasn't hard. Therefore, it is now better for "me" to have them remain since I gain information compared to otherwise.
Most shoujo are shit though even if I rag on the hate. My list is usually like a dozen in count, which is not a lot.Oh well. I still recommend checking it out when it's done and over with.