Keyboard Movement

I've read around on other topics about this and don't understand why this isn't an option. I've wanted to use W-A-S-D to move since I started playing and complained for days to the friends that got me into the game but dropped it after while. Then I started playing the game Battlerite in which they did this idea almost perfectly, so I know it's definitely possible. I've heard arguments from both sides saying that it'd be unfair making kiting too easy or pointless because mouse moves you in more directions but what does it matter as long as everyone is able to do it. Why would more movement options be a bad thing for a game?