In a interview, Negi talked about how he doesn’t like the “first girl” trope, So to avoid people saying “first girl wins” he introduced all 5 of the quints in chapter 1.
However the editor made him introduce Itsuki first (and have her in the centre in the Vol 1 cover) to make it easier for readers to understand.
What I think the editor means by this is that he/she thought it would be easier to introduce each of the quints one by one and have each get their moment of spotlight, rather than all at once which is what Negi had originally intended, and Itsuki had the best personality to kick the plot into gear (that’s just my interpretation though).
Moral of this little info drop is that all the quints have a chance since they’re all “first girl” making the first girl trope null void. So for all you saying you don’t like Itsuki/don’t want Itsuki to win because she’s first girl, you can relax now because if does indeed win, It won’t be for that reason.
Oh and If the last chapter didn’t drive the message home that “Harem ending ain’t happening” to you, Negi confirms that it ain’t happening.