When using calculate field (multiple) with Arcade there is no large expression block like there is for calculate field (single). The expression field is a tiny input box that makes writing complex expressions for fields difficult. You can get around this by putting all of your arcade code on one line, but this makes it difficult to debug and read.
It would be very helpful to have either a) a way to expand the expression input box to the same size as the one for calculate field (single) or b) the expression block replace the code block when Arcade is selected. The "code block" is used only with Python but continues to show even when Arcade is selected.
Either one of these solutions would make writing and debugging Arcade much easier when using the calculate field (multiple) tool.