Google announced today on its Developer Blog, that it will begin reviewing apps for WearOS later this year. This change is to help make the apps available for WearOS a bit more high-quality. It is also being done to help clean up the Google Play Store, when it comes to WearOS. Google has been reviewing WearOS apps since Android Wear 2.0, however that was optional. Beginning in October, it will become mandatory. For new apps, it is going to be mandatory starting October 1, 2018, and existing WearOS apps will need to be reviewed by March 4, 2019. Google does mention that the review process for mobile apps will not be changing, and that is independent of the WearOS app reviews. Additionally, mobile apps will not be blocked if they fail the WearOS app review.
The whole idea here is for the experience on WearOS to improve, by providing better quality apps to its users. Google is outlining the criteria for WearOS apps. But the biggest things they need is to support different screen types and have a WearOS screenshot available in the Play Store. Supporting multiple screen types is important since most smartwatches do sport a circular display, however there are still some that have stuck with a square or squircle screen. Also, some of these screens are different sizes. Google is also going to allow developers to opt of these app reviews if they are on a beta or alpha track. So if you are developing a new app for WearOS, you can opt out of the review process until you are ready to launch. This means that you won't need to wait for it to get reviewed before testing it out.
Obviously, app reviews is something that Google should have made mandatory since the beginning of Android Wear, to make the ecosystem better. But it's never too late. Now if you are a developer of a WearOS app, you're going to want to submit it early, as it's likely that the reviewers at Google Play will be quite busy once those deadlines come up.