Because I don't think it is needed. MK11's plot is likely going to be even more complex than MKX's. With more plot and diverse characters, having too many would result in the story mode being utter chaos. We were close to that in MKX. I don't want them to repeat the same mistake. I want all characters to get equal space for contribution. In MKX it felt like some characters were there just for the sake of it, others were held back because of not enough time, some got average screen time and some were overexposed at the rest's expense. I want every MK11 character to have a meaning and reason why he's there in the first place. If they add again a bunch (8+) of newbies, can you imagine them doing all of the characters justice? I can't. You want the new guys to shine, old new guys to shine, obsolete classics to shine, newer classics to shine, bad guys to shine and all of it to make sense. 4 brand new characters is plenty as long as they are unique and different from each other.