Google announced bulk uploads for ads and ad groups in AdWords today.
"Imagine you download a report from the Ads tab and want to test different creatives in ad groups that are underperforming," writes AdWords Product Manager Prashant Baheti. "You might also want to turn off certain ad groups, or change the budget for others. Instead of toggling back and forth between AdWords and your spreadsheets, you can now download reports from the Ads and Ad Groups tabs, make changes directly in your spreadsheet, and upload them directly to your account."
"Uploading changes to your ads and ad groups is simple," adds Baheti. "Just like with keywords, when you download a report you will be prompted to make the report 'editable.'"
After making changes, you can save in CSV, TSV and Excel formats. To upload ,click Reports and Uploads on the left side, and then select Uploads. From there, you will see the Upload Type column. You can only upload one report type at a time. If you want to make bulk changes to both keywords and ad creatives, this must be done separately.
Once you bulk upload, there's no way to cancel the automatically reverse the changes. Something to keep in mind.