Not to defend pinch to zoom, but If you need two hands you may want to change how your holding your phone. Index and thumb on the screen, other three fingers to hold the back.
I've hardly ever seen people zooming with one hand (one hand on the screen, sure, but the other hand holding the phone). Maybe it works for you but, having just tried it, I find it very clumsy.
I've just looked through a load of random videos of people using their phones on youtube and I didn't see a single one where people are holding it with 3 fingers behind and two in front.
For zooming, I've always used the double-tap method. This generally works fine for zooming in and out on Safari, and it works for zooming in on Maps. I can do a two-finger double tap on Maps to zoom out, but it's still pretty awkward so I'll keep switching to two-handed mode for those (rare) instances.
And now I know about that! It's still awkward, but slightly less awkward than one-handed pinching.