No, it's not losing creativity. There is so much unexplored by Pokemon, in this two generations, Gen 5 and this one, they've started basing regions on other places in the world whereas the previous ones were Japan based. There are so many places in the world left to explore: Continents like more of Asia, Africa, South America, Australia, more places in America, etc. Pokemon are mainly based on animals and there is still many left to cover as there are literally millions of creatures in the world, other than that they've based Pokemon on inanimate objects( like the Rotom appliances),Robots and even aliens. Also there is a ton of mythology worldwide to draw from.
The point is I dont think Pokemon will lose creativity when there is so much out there to draw from.