I used my three favorites as an example.
The actual point is the question of Cassie Cage (or any meh-character) getting time, money and other resources put into them instead of fan favorites, which would please more fans. I have legit not seen even one single positive comment about Sonya Blade making it into the roster. On the other hand, I've seen plenty of people complaining. Does that cover the vast majority of the players? Well, in Sonya Blades example probably not, since she is fairly iconic... but Cassie is not. Neither is Kung Jin and neither is Jacqui.
Then there are the people, who think that "casuals don't care about old fan favorites ninjas and other cool characters". We were all casuals back in the day, before we witnessed some of the great MK characters and established them as our favorites. It doesn't matter if someone knows Smoke right now or not... The point is, that if you give them two games: one with Smoke and without Cassie and then one without Smoke and with Cassie... chances are probably very high, that they'll end up preferring Smoke. He has so much more style than Cassie. And the same can be said for so many other characters, which might remain in character limbo, because Cassie took their place.