It was a good thing they removed them off the app stores because rovio has significantly increased the difficulty of the levels to the point where its impossible to beat them without powerups, instead of skill. Back in the day, you could beat the old angry birds games with 3 stars on every level without using powerups but that has changed. They make you use powerups, and you also have to be very very precise to get three stars, even on the tutorial levels. Speaking of precise getting all the mighty eagle feathers is also very difficult because you always have to aim perfectly, and the mighty league? Yeah, they aren't really players, if anything, I honestly think they are just ghost data of previous players.

This is why I enjoy playing mods of angry birds on pc instead of my phone