Marci you cannot argue with Webflow, when they say they’ve done internal testing and have the stats… After all their latest pricing was validated with internal research! 
So was their third redesign of the whole site (nevertheless they did a fourth one of the main page ). I guess they also have bullet-proof evidence that the new way of moving elements in the Navigator is easier (Moving elements in the Navigator) or that the Symbols panel placement needs no further fixes (A better Symbol panel | Webflow Wishlist), or that the Color panel needs no close button (Close button for the Colour (color!) Palette window | Webflow Wishlist)…
After all you get what you pay for - unsubstantiated price increase leads to unsubstantiated product tweaking