Dear Student,
Wa 'alaikumus salaam,
With respect to your issue of concern, in addition to the respectful inputs as go above parting with deep insights into the subject and given the Qur’anic position with regards to the obligated responsibility of prescribing a ‘wasiyah' amongst believers, may I also share a humble opinion from my view.
Firstly, in as much as one would suggest a contingent option to a given divine religious prescription/ delegation, it must be maintained that such a fallible alternative has neither theoretically nor practically been divinely sanctioned explicitly and that there’s no religious solid grounds to justify it in preference over the recommended one. With all due respect, to use fallible and contingent justifications such as ‘...fear of alteration (2:181) & settlement of court battles b/w siblings, rancor, severance of relationships etc (2:182)…’ is to inherently assume that the divine delegation did not take that into consideration or at least overlooked its potential impact. Either way, this has to be proven. Furthermore, problems such as ‘…rancor, severance of relationships etc…’ remain contingent to the situation regardless.
In my view, the Qur’anic prescription towards the matter proffers an ideal avenue to the testator through which they prescribe a manner in which their ‘legacies’ are to be shared post-death as appropriate. In this context, it also inherently assumes an ideal Islamic family setup as well as an ideal ‘executive’ system under which fallible 'trustees' are to faithfully deliberate the same amongst and to fallible believing Muslims. Any inconsistency or potential inconvenience to heirs remain exactly fallible i.e, subject to human fallible character (testator, witnesses, executives, heirs, etc) and not the divine infallible delegation (wasiyah idea) itself - with respect to its time aspect whatsoever. Nevertheless, some human shortcomings are also recognized and ways to curb them suggested (5:106-108) even in other dealings (2:282-284). Even so, in the context of whatever potential uncertainties, we have to humbly submit our endeavours into the remit of our abled capacities (64:16).
It must however be pointed out that in the divine delegation, even the human function has been provided for where one is given chance to determine the respective shares as deemed appropriate by the testator - with no potential compromise (ghayra mudhwarin). Thus, in my opinion, to argue for the human function in determining the appropriacy of the time aspect for ‘wasiyah’ execution (where it has not been given despite it being provided for at another level) would be akin to providing for human intervention of the divine prescription. This is before even looking into its impact with other aspects such as other prerequisites to the 'inheritance' distribution i.e, debts (4:12).
Hopefully that also slightly gives some perspective into the subject God willing.
And Allah knows best.
Regards,
Athman.