That feature of the new blockchain wallet is called an HD wallet. It was implemented to enhance the security and just like what they have already mentioned, it is for the reason that you will not have not re-use the same address. HD wallet generates new address but it still is from the same wallet so which means all previous will still be able to receive bitcoin.
If you want to have an ordinary wallet, you can create one from a different wallet then export it and import it in your blockchain.