It seems that Valve still uses an individual approach.
Recently, some developers have started saying that Steam has allegedly introduced a ban on launching adult games in early access format. For example, Dammitbird stated this.
A developer contacted Steam support directly with a question — a specialist denied the reports of a "ban"; an individual approach is used in the assessment:
“We evaluate each game individually during reviews of its build and store page. There is no single rule prohibiting certain games from using the \"early access\" model for development.”
It is noteworthy that this answer contradicts what Steam support stated a month ago:
We do not distribute Adult Only games that are in \"early access\". Sorry. You can update the game after release, however, if you are adding additional adult content, we ask that you release it as (potentially free) DLC.
