Would expanding those credit requirements help?
Just MHO, but personally, I doubt it. I think you need to take the 400+ level courses to get into the depth of things, and from what you garner from a couple more miscellaneous courses probably isn't worth it.
But, luckily its easier to become well-read than it is to become proficient at math, engineering, or physics. If you make a list of 40 books or so, say two dozen classics of literature, a handful of political treatise and several historical books, you can probably get what most 4 year liberal arts majors retain.
That said, I'm only moderately well-read. It's still a work in process for me.
On a related note, tonight I just finished a book of short stories by Hemingway called In Our Time. I've read A Farewell to Arms, For Whom the Bell Tolls, and The Old Man and the Sea, and this is my favorite Hemingway by quite a bit.