I wouldn't say that Android development is any harder or easier than writing a script. It's merely different; with OSBot you are given a specific API that allows you to easily interact with the Runescape world. When programming Android applications, you also have an API that allows you to easily interact with your Android device. You shouldn't have any difficulty learning the ins and outs of the Android API if you decide to learn it. I would personally recommend getting a book on Android development, as it will go much deeper into the workings of the Android system than a video tutorial will.
Good luck to you and if you need any assistance, feel free to ask!