For about a year now, Google has been busy transitioning to larger text ads. As of February 2017, it became impossible to create, copy and paste or edit the old style text ads. You’re able to pause and unpause them, and that’s all you can do with them
Because of that, the push to the new format has been accelerated, even if the only thing you’re doing is changing a landing page URL, you have very little choice at this point but to write a brand-new ad to go with it.
There have been many expanded text ads that perform better than standard text ads, but there are many that also perform worse. Depending on other publshed articles, there are some advertisers that have struggle with the process and have seen a mixed bag of results.
An article by Ted Ives, runs through why he thinks those who have struggled and then details his recommendations for overcoming these difficulties with ad writing.