Here’s the old-fashioned version of that: Thomas Jefferson’s Bookcase. Having built a book case inspired by this of this out of oak, I’ve noticed no deflection. (It’s structurally different, center-keyed box joints instead of dovetails, thick plywood back, various clear finishes.)

However, I can tell you that there are a few functional problems. One is that the shelves do slide against each other. The little nubbins would help, however, you’re cutting the fibers of the wood or into plys. That could increase deflection. I bought some handwrought nails and may end up using them, but I like the modular nature. Another is that these shelves are not light. I had hoped to make them easy to move, but they are not light. Finally, there’s no cover, so books fall out as they’re getting moved. Barrister bookshelves solve these problems.

If it’s bark or shaving it down, a drawknife is a perfect tool.