Maybe the worst for peak power, but the switch to the V6 has a lot of reasoning behind it. It is more compact and lighter than the I6, its cheaper to build using less materials. It is much smaller especially length wise so easier to fit in things. (In europe, cars now must be "pedestrian safe" so they have huge spaces in front of the motors that are made to absorb the impact of the pedestrian before he hits the engine block and splits his skull.)
The V6 most likely wont ever make the same power, but its bound to be more efficient because toyota never steps backwards in that department, less rotating mass due to a smaller length crank might also make for better gas mileage along with other things.