The way I see it, both the challenge and the response text fields to "wrap text" if the text is longer than the available width. And it does this in a smart way by dynamically distributing the overall column width to the challenge and response fields. For example, if the Challenge is short (e.g., "Gen") you get the entire remaining space to the right for your Response, and vice versa.
So even at this stage, you already get the best of both worlds. Use 1-line height for checklist items that don't trigger "wrap text", and allow 2-line height entries for checklist items with longer text.