This substantive shift in the law was a sharp reversal from precedent, legitimately causing the petitioners not to raise the issue on direct appeal.
A second substantive change in the law that removed an alternate basis for the sentence of one of the petitioners did not trigger a mandatory limitation period for filing the writ, as it would merely have shifted the ultimate basis for the sentence.
A plea deal carve out excepting any constitutionally impermissible factor incorporates any unconstitutional input present at sentencing.
Prior offenses should be considered categorically when deciding whether the conviction is a valid predicate.
(Important decision. Again, all this is quick work. Don't rely.)