I'm also removing Opera from my machines. I have no interest in running the only browser that won't let its users pick a search engine.

This whole situation (including the speed dial page) smells a lot like a backroom deal between Opera and Google.

So let me make sure I'm understanding this.

We can't have a UI to add a search engine because malware could use that to add a malicious search engine.

Instead, we have to edit a JSON file to add a search engine... which malware TOTALLY can't use to add a malicious search engine.

Ultimately, sufficiently advanced malware is indistinguishable from the user, regardless of platform and regardless of method (simulated clicks, file edits, etc).

On Windows, the best you can probably do is put the JSON configuration in Program Files, where editing it require admin privileges. If that's the intent, though, then why are you overwriting it and making me angry all over again with every update?