The WebKit team is great. Look at all the web standards being worked on. Look at the ES6 progress. They are pushing the state of the web forward on iOS.
Now put some of that same energy in WKWebView. Open it up. We need more than just loadURL()
The whole point of having different browsers is to have competition (which means better performance/new features), but currently in the iOS world there is Safari and multiple reskinned Safaris.
That's not a valid reason. With per-app sandboxing. At worst a non-Apple native browser that escape the confines of the web page and be subject to app security.
That amounts to using "security" as an argument for not being allowed to do something with the reason as, "Because we're smart and you're not".
I have mixed feelings about giving third-party applications (browsers) this permission. Bugs can lead to remote code execution, can lead to sandbox escapes, can lead to compromised devices.
This is a really tough one. Specially for apps that load random content from the web.