To add my thought, your suggestion could be worded something like:
I propose that the Current Last name should be left blank unless there has been an event that changed it from LNAB.
The current functionality is that when a profile is created, LNAB is copied into the CLN field, if left blank. Therefore, the code needs to compare the 2 values and if there is the same string of characters, assume that there have been no changes. i.e. most Western males, have CLN and LNAB the same due to not changing it when marrying. It would be incorrect to display my name as David (Weinberg) Weinberg. One way to display a woman that married a man with the same last name would be to leave CLN blank unless it has changed.
This would require a major change to the existing WikiTree profile data. To implement this suggestion, all profiles with CLN and LNAB the same would need to be assessed to determine if the CLN should be removed. To do this automatically would potentially create the reverse of the current situation. Eliza Kelley would have her CLN removed and would still display her as Eliza Kelley rather than Eliza (Kelley) Kelley.
Blank CLN by default, would also require changing every time the value of CLN is used, to add code to conditionally use the value of LNAB if CLB is blank.
Alternatively, there could be logic introduced to the code to establish if a life event took place to justify Kelley and Kelley not being the same, for example, if there is a spouse. But as has been mentioned, not in all cultures does a last name change following marriage. For example, Spanish female, María del Carmen Barrenechea Montegui kept her last name and it would be incorrect to display her as María del Carmen (Barrenechea Montegui) Barrenechea Montegui even though she has a spouse.