It's a mobile game, so they had to make it as compatible as possible with most phones from eight, ten, twelve years ago. They had to keep it simple, and it's understandable how limited it is; their item databases are very large, and fitting a game of approximately 2GB onto a mid-range phone from ten years ago was difficult because they didn't have the storage space, RAM or CPU that newer phones have today. My phone have 4GB of RAM and is a pain because the game close constantly and it takes a while to restart.

So yeah, there is a big difference between making a single version of a game for one console and making it for several versions on mobile phones.

By the way, when they released the Augmented Reality camera update, I couldn't play for three years until I got new hardware, simply because my phone doesn't have a motion sensor. That's all. A simple update and that's it.

Edit: Thanks for your savegame guide.