Tried out the ws tester today and been thinking about better layout since it is rather bulky today
I'll attach a mockup of it but in "short" its:
1) Reduce redundant text (i.e. XXX instead of Request XXX)
2) Make input field directly visible (less tabs)
3) Avoid text buttons where icons can be used
4) Remove duplicate functionallity (tcp monitor does not seem to provide functionallity outside of what tcp monitor does)
5) Let the output be Save, open in editor based on content type, show "raw" and show in "embedded browser"
6) Tab and save input between sessions to avoid retyping.
7) Consider add history back/forward buttons ?