- Vertical reading space is limited
- The toolbar is aligned at the bottom of my screen which causes me to run into the OS X dock, which I set visible on hover
- It compresses all message recipients (To, CC, ...) into a single row which makes you have to double-check if everyone's in the right place
- The formatting popover appears over your content if you want it to persist
- I feel verbally limited by its small writing area
- They haven't solved the "too many IM and compose windows are open" problem. When you get into this situation, things feel really crowded and messy.
- The hover state on the formatting toolbar "+" is jarring because the item you hovered over changes underneath you, making you (sub?)consciously worry about a misclick since it will launch a damn-obtrusive Google Drive dialog
- Between the appearance of Gmail as a whole, and this as an addition, my feeling of information overload when dealing with email has only increased. Gmail just isn't very "zen."