I would support the introduction of child-parent phasing and have thresholds like this:
Both unphased: Largest segment at least 8 cM
1 Phased: Largest segment at least 6.5 cM
2 Phased: Largest segment at least 5 cM
X-chromosome would be treated like the autosome, so a largest segment could be on the X.
Rather than the complicated "a 9cM segment OR 7.69cM segment AND 20cM total, on the autosome"