Finally being fed up with the inherent front derailleur STI shifting bug-a-boos, I switched to bar ends. Now there's no more shifting problems. This allowed me to switch to Dia-Compe 287 V brake levers, so I can use a variety of brakes and not have to augment with Travel Agents. Another benefit is that I can tell which gear I'm in by just glancing at the shifters.
I already had bar end shifters on a couple of single bikes so was used to lifting a hand from the handlebars and moving it to the shifter under any condition. This can take some finesse with a stoker moving around. So a little practice steering with one hand might be prudent before switching.