Sugest only translated units
Handle units with plurals
Make more_like_this not return matches already returned by same_source
Better error logging from machine translation (include exception name)
Do not confuse machine translation source with translation source

Let's name this service in this case.
Inclute translation source in mt page

This way translators can identify where does it come from.
Drop similar string page

It is obsoleted by new machine translation interface.