Google Web Toolkit - Reviewed and Disappointed

I wonder why the GWT is designed this way, some points get me stopped
looking more into it or even consider building a web application with
it.

1. it's in Java programming language, which over-complicates lots of
things.
2. existing projects cannot integrate with GWT, it will require a total
re-do of everything.
3. compiling and seeing things in action is such a pain such that to
change anything and see it in action take longer time.

What else can I say... maybe I should go for YUI (Yahoo User Interface)
instead. This GWT from Google is really disappointing.