How have they made it so anyone using their engine is a 2nd class citizen? Does the engine perform differently outside Safari?
You can use UIWebView, the older interface. The biggest problem is that its JavaScript engine is slower than Safari's, and does not JIT compile code (according to Apple, this is for security reasons). I've also seen complaints about scrolling performance.
You can use WKWebView, the newer interface. Its JavaScript engine does JIT, and it boasts 60fps scrolling. Unfortunately, it's missing several features detailed in the bug, including a way to clear and manage cookies, custom URL handlers, POST request bodies missing in certain cases, etc.
One would hope that the WkWebView bugs and omissions will be addressed in future iOS versions, but today is not possible to make an iOS browser that works as well as Safari.