billiesue, Arts & Crafts (Craftsmen) houses are full of such details—they add charm but typically are designed so as to make sense both inside and out. This looks, to me, like a modern adaptation/imitation rather than one designed from the Arts & Crafts aesthetic. Precision, excellence in joinery and functional nooks and crannies make the difference.

In this situation, I would be inclined to design a bench for seating/shoe storage with a narrow storage/book tower on either side with a well proportioned opening to the stair behind. The back becomes a wall, balusters eliminated and a rail mounted such that it is not visible through the opening. There are a lot of complexities in the design—so not doing one up for Houzz—but this would create a deliberate character space rather than a fix to hide a mistake. A design detail (shape, profile, etc.) would be carried over to the window surrounds so the whole space hangs together.

Hi13, I'm curious to know whether the house was fully drawn (including details such as the stair rail) prior to construction. Where a detail is unexpected or out of the norms a client might expect, it is a good idea (for us Pros) to provide an elevation to get approval/direction. From the client side, whenever you assume something is X, verify! Don't worry about being a pest—it's your money and, more important, the space you will live with every day.

Good luck.