You can still use the Keyword planner tool without having to create a campaign. Once you login to your AdWords account, click on Tools on the top navigation panel, and select Keyword Planner from the drop down list.
The tool
menu is not available anymore even though the manual show it as an option.
Now there is only a wizard with few options to choose from.
This issue seems better suited for the AdWords Community Forum since this forum is focused on AdWords API. They should be able to help you with your issue.