I've looked at all of the libraries listed in: Best GWT widget library?
Honestly, gwt-ext looks the best, but it's no longer being maintained (and the old project lead for some reason recommends SmartGWT instead.) I don't like the approach of SmartGWT, both because it wraps Javascript, and because it wants me to wrap my backend classes in its various data components (I don't want to have to translate my model objects just to use its widgets). Vaadin looks nice, but again doesn't seem to want to let me just use it as a client widget library; I have to use its server components. GXT looks fine, but the open source license doesn't apply to my organization.
Everything else on the list hasn't been updated in a long time.
Is there no GWT widget library that just focuses on providing better widgets, and doesn't want to force you to use its architecture to develop your UI?