HTML5 stinks on Android (due to bugs and fragmentation) and HTML5 stinks on Win8 tablets (due to IE10 bugs, implementation differences, also supporting mouse and touch together is hard to get right due to event models). So it regularly doesn't make any sense to try and build a cross platform HTML5 solution. If you are producing a content app or business app, you might get away with it... Or if the app only needs a si…
Why on earth would you disable pinch zoom on mobile web? It is the most useful feature, it allows the reader to adjust the amount and size of text displayed. I use it all the time and despise those web apps blocking it. Html is elastic by nature, and html 5 will win over native apps because it is elastic.
I've also heard many arguments that responsive design makes pinch-to-zoom unnecessary. A page should automagically adjust so that it's optimal for a 27" monitor, a 2" mobile display, or anything in between. It's a great idea in theory, but I've yet to see it executed well in practice. I guess it's exceedingly difficult to design an effective UI that can automatically and seamlessly scale between a large-format screen and a small-format screen.