The danger is that changes to screen size aren't always reflected by the software, so you may have a small screen that scales down, or a large screen with wasted real estate. See the host of apps that haven't update for the iPhone 5 screen yet!!!
Keep in mind that the Android SDK has quite a few features that allow you to create liquid layouts that will work fairly well on most device sizes, as precisely because the Android OS comes on a great variety of hardware, this problem had to be addressed early on, while on iOS every time a new screen size/pixel density comes along you have to create an all new view.
I'll acknowledge that many times you have to fiddle a bit to make sure that your Android view works well on a variety of screens, but usually you can target between 3 and 4 layouts and have a usable UI for all devices from 10" tablets all the way down to small feature phones.
The danger is that changes to screen size aren't always reflected by the software, so you may have a small screen that scales down, or a large screen with wasted real estate. See the host of apps that haven't update for the iPhone 5 screen yet!!!