I've read through the style guide on name fields but I'm not really finding a satisfactory solution to the problem of someone changing their middle name. I'm not sure how common this is, but my mother, my half-sister (by my father), and my wife all changed not just their last name but also their middle name upon marriage, removing their given middle name and using their maiden name as their new middle name. None of the current fields seem correct and I'm mostly resorting to just putting that detail into the Biography and leaving the Middle Name as the middle name at birth.
In addition, my mother presents another interesting issue in that she always went by her middle name anyway, and so she changed her first name as well upon marriage. Basically, if her name at birth was Ann Beth Smith, then after marriage became Beth Smith Jones. I've followed the guide as best I can and put her current first name as her Preferred Name, but the end result is all sorts of bizarre outputs in different context. For example, the Formal View is now
Mrs. Ann Beth (Beth) Jones, formally Smith
and Abbreviated for Privacy looks more correct than Abbreviated for Space, which is odd (privacy gives Beth B. (Smith) Jones, which is mostly right, but space gives Ann Jones, which has never been her name) and other little oddities.
I think ultimately it would be nice to have a supported Current First Name and Current Middle Name field to go along with Current Last Name and the less formal Preferred First Name and Other Nicknames, but until then is there a better way to handle this than what I'm currently doing?
I put a wikitree ID in for my mother as an example, but it's a private profile (she's still living) so I doubt it will be much help; you'll see the nearly correct Abbreviated for Privacy view of Preferred First - Middle Initial (LNAB) - Current Last.