The Nexus 6 is 1.1mm taller and 5.1mm wider than the iPhone 6+. There is very little difference between the two sizes. It is just the Nexus 6 has a much bigger screen due to having smaller bezels.
And they aren't forcing bigger phones. They are still offering the Moto G GPE at 4.5 inches and the Nexus 5 at close to 5 inches.
Good to see someone else doing research instead of spouting FUD. The N6 and 6+ are nearly the same physical dimensions, but the N6 better utilizes the frame to include a larger screen.