It's perfectly reasonable to expect extra data to be collected when using prerelease versions of software. Complaining about it now is premature.
I'm not accusing you of this, but in other cases I've seen proponents of something say "This isn't a big deal, it's just starting out". Then, when people continue to complain a year from now, the defenders say "This isn't a big deal, it's always done this."
Vivaldi looks interesting, but I'd wager that there's a decent overlap between the Power Users they're after, and the group that values their privacy the most.
This is incorrect in the world I live in, and I do not want to visit a world where it is correct.