Well, there is some of that - your very own fishing log! While I was working on collecting big fish, I'd read the entries in the fishing log. They go into a lot more detail than the text on the fish itself.

If you've been collecting Triple Triad cards, that's another source of good lore at your fingertips while you're angling.

I've found some tidbits of interest going back and reading old quest logs, as well; sometimes they reveal things that I didn't pick up on while doing the quests myself.

Certianly, I have no objections to adding new lore of the type you describe - can never have too much! - but there's quite a bit available to us even right now.