Hello, i'm using webflow since a couple of days now and here are the improvements i suggest:
Out of the box, per template limited webdesign resources such as sample images / modern flat animated gifs for sliders or portfolio and demo team.
Font icons and predefined but customizable UI kits.
Could be great because it´s sometime hard to find and manage those assets. It can also be time consuming. So with this kind of features, we can even more focus on working on layout and style.
Implementation could be done like adding google web fonts from the WF dashboard.
It can be considered as spoon feeding but hey, you guys already did it by creating Webflow
Hope it will help!