Off the top of my head:

• complex gestures (tap + swipe, two finger swipe/rotate)
• frequent/recent/new apps in app search
• app drawer tabs
• icon customisation for folders
• creating home screen shortcuts for activities (or if that's possible, I couldn't find it).

Of course this shouldn't sound as a blame - I know Lawnchair is relatively young - those are a bit more advanced features that I grew used to over more than 10 years with Nova. When I manage to get a development environment running and some knowledge about Android, those are some of the first things I'd try to implement in Lawnchair.