Have you checked this?
I have never ridden a speed triple, but I don't think that the effort to roll my throttle is excessive. Have you checked that the throttle cable moves freely within it's sheath? When the throttle cable becomes worn or kinked, the damaged strands of wire can cause binding within the sheath. Also, the plastic bit that guides the throttle cable within the switch cluster can get gunk in it or become damaged and cause cable binding. The most common result is that the throttle sticks and doesn't return to idle when released, but it's possible that the problem can cause excessive drag resulting in increased effort to operate the throttle without increased drag in the return direction. If you take your throttle cable off the bike, you can play with it and see if it moves freely without anything else (like binding at the carburetors) interfering. If the cable does not slide back and forth with little effort, then clean and lubricate the cable. If that does not fix it, replace the cable. I have had my TBS since 1998, and I have never had a problem at the carb end; it's always been the cable.