This nicely highlights a problem I see with controlled app store models. I would like to give this a try but looking at reviews I feel like I might not like it (always visible address bar, bigger text). So I might want to downgrade which is not "allowed". I am glad they let users move the navigation bar to the bottom, that is much easier to reach with one hand. I wish there were site specific preferences like on the…
Well they did have Opera Beta with webkit as a separate app in the appstore for quite a while, that's a good solution for not-liking-thus-downgrading issue.
Also, on the Play Store publishing page, there are features for beta and alpha testing, not sure what they do, but I feel they are relevant as well.