Actually, there is. It's a proven fact, especially on older devices/smaller devices, that Mobile devices cannot handle that much graphics intensity. They have a smaller graphics card. Not to mention the screen is smaller, making it easier to get killed. Therefore, this is not a bug and was an intentional change to spare some people. Case closed, but feel free to argue. I'm good at proving people wrong.
Not to mention that most of the mobile community is MMO gamers/people who have played other games by 505/People who don't know what the

they're doing. This could also be intentional for it to be easier for the mobile gamer audience.