this topic is quite curious, I mean, it made me wonder why maria doesn't have a lot of important parts, maybe your story is very stupid, but what if maria would have been controlled by shaft firstly?, and then richter came up to save her, and in the process, being controlled too, and then, alucard coming to save the day, maybe they could have edited "the 5th ending", and could have done something like...emm, if you complete the game 1st time, you get richter playable, and by getting 180% or more, you get maria playable....that would have been wierd too, but, i see more sense in my example than in yours, since maria has amazing powers....no way she could get killed by richter as a sacrifice...
and sort of a question comes to my mind when I think of this......what if, after she would have been captured and taken off from her powers....and fulfill all the requirements to be sacrified(100 years after), drac doesn't come to life again??
OMG!! she wasn't virgin!XD