I have flatbars with bar ends on my Trek 7500FX along with LX-XT drive train and have used it for both touring and riding centuries. It's a perfectly fine setup that works well and is comfortable. It's only in headwinds that I miss having drops, but you can hunker-down a bit with barends. Speed is not an issue when touring, at least when I tour.
When I want to ride fast I ride my Lemond.