That might have helped, although then you have the problem with marketing. The entire point of a diverse cast in these games is that new characters function as tools to try and appeal to new audiences and markets. You create new characters that have appeals to certain types of things people like in order to bring in the weebs, or bring in the edgy kids, or bring in lgbt people, or bring in the trolls, etc etc. This character marketing relies on people identifying with the persona and fantasy of the character.

If you're a summoner and not the character, you lose some of the marketing effect of this because characters stop being identities to players. That'll be a major part of why they cut that out.