As someone who gets the shakes from looking at too many parenthesis I think it's a great step in the right direction.

A few weeks ago I went through the "GUI demo" source, and it's not bad. Of course just reading it doesn't tell much about what's the IDE support, how easy it is to figure out the arguments/types. (But it's rhombus/static, which is encouraging!)

https://github.com/racket/rhombus/blob/master/gui_demo.rhm