I doubt they're going to change anything about Cliqz, as there's no actual privacy concern with it. There's the technological feasibility for Cliqz GmbH to steal user data, but Mozilla owns parts of Cliqz GmbH, so knows what's going on inside the company and they have a contract with Cliqz that prohibits the storing of personal data.

Mozilla has also made an official statement saying that no user data will be stored, so break that promise would be misleading of customers, and their Privacy Statement does not constitute the storing of such data, so allowing it anyways would count as violation of contract.

Additionally, they're testing it in Germany, where this sort of hidden collection of data either has to be obvious (for example, if you order something online, it's clear that they have to process your address), which is clearly not the case with Cliqz, or the user has to be prompted for opt-in, not either the case with Cliqz, or it may not be personal data. So, if it were personal data, they'd be violating German law.

And the handful of shitstorms in tech-focused online communities are hardly the end of the world for Mozilla. Making the internet rely less on search engines, which is what they're ultimately trying to achieve with Cliqz, is more important than that.