National Instruments will not be implementing this idea. We are not planning on making any cosmetic changes to the Expression Node in LabVIEW.
For reasons outlined in detail in this idea, the the expression node should be redesigned. These vertical lines are too thick and the end arrows are pointless and too busy.
After all, the expression node is basically a [single line|single variable] formula node and for this reason it should look more similar to a formula node.
Here is my suggestion for the redesigned expression node (on the right). The current design is shown on the left for comparison.
Note that the grey left and right borders are exactly matched to the border design of the formula node, making things consistent and intuitive. (Top and bottom should remain single pixel to save diagram space).