Don't touch my WinBox, it's one of the best tools invented by mankind, and it's perfect as it is now. It's like trying to reform hammer, sure you can come up with something else that's not bad either, but it still won't be good replacement for the simple and reliable tool in all cases. Native WinBox is exactly the right way to go.
Previously I wasn't very excited about browser-based UIs, but since I've been forced by VMware to abandon their native client for ESXi and use the new html-based UI in browser, I've turned into enemy of such solutions. You can say that it's just one case and it doesn't prove anything. But is there any, where someone had perfectly good native application, created new html-based one and all users were excited, because it was so much better?
I'd argue that since WinBox is pretty stable and doesn't change much, it would now make sense to make native LinBox, MacBox or WhateverBox. It would be some extra initial work, but once done, further required changes would be small and infrequent. Regular support for new RouterOS versions is now done using definition files shared by WinBox and WebFig, so nothing special for that would be required. Only for things like for example recent change in authentication.
People who quote full posts should be spanked with ethernet cable. Some exceptions for multi-topic threads may apply.