Correct me if I am wrong, but I have never noticed an option for two-factor authentication
on BrickLink and I think that in this day and age most websites and services
should include it.
So...
I propose the addition of two factor authentication (via SMS code).
2FA via SMS code is a stupid idea and all kinds of security experts are recommending
against the practice (including NIST in the USA). If they are going to implement
2FA they should use something like U2F https://en.wikipedia.org/wiki/Universal_2nd_Factor
which has none of the problems of other 2FA solutions. Such a solution would
(if implemented properly) completly stop the hacking attacks that have plagued
Bricklink in the past.