So the bike can be placed in the corners better without dragging the **** floor boards! Also so the rider has more "feel" for the bike instead of feet placed to far forward.
Explained in plain English around 0:52 of the video.
Triumph Rocket III Roadster - YouTube
Triumph most likely saw the problem that they had a great handling motorcycle that had a potential to go lower but couldn't because of the floor boards. They changed that for the better on the Roadster. To far forward is a position that's for touring bikes and laid back cruisers. In some magazines I have seen they put the Roadster in the "naked bike" category rather than the "cruiser" category. Even though Triumph calls it a cruiser it does look like a naked bik.
It's really according who you ask. You like floor boards so it's not going to be "better" or "good" for you. I don't like floor boards so I think it's perfect. So Triumph......in fact.... did something that made it better.