Has there ever been a good game that does this?
And I don't mean torn clothes or defeat scenes in general. I mean when clothing state is directly tied to current health and any healing magically also repairs the clothes. To me this usually tells the adult content is very detached from the general gameplay and usually it also means very poor design quality in other areas as well. Then again, the 2D is also blonde while 3D seems raven haired so it's not our only clue...
So, did somebody try making an action game and when it turned below average did they glue on some naked art in attempt to distract you from noticing? Or is there something to see here?
It's an anchronism of old h-games that used simple state flags to give the illusion of combat h-mechanics and has just sort of stuck around as a lazy way to lead into GOR or provide extra "content." This is the bulk of Japanese porn games I feel, mostly lazy/inept developers who keep games simple to peddle artwork (a lot of them are just artists themselves or super small teams). On the plus side that also means they produce a lot of content (I think JSK releases most games on a 6 month cycle) as opposed to 7+ year hell of incremental western releases.
As you mentioned, usually it's a sign the game is a HCG viewer with game mechanics (mostly baseline rpgmaker stuff, generally a reward/punishment with no story persistent effect to story) as opposed to a game that incorporates h-mechanics into gameplay. It could still be third type where the it is a two in one game that has H-mechanics as part of gameplay but separate from storytelling and/or combat mechanics.
Now, whether it's good fap material is entirely separate issue. That has more to do with pacing, content, and delivery which enjoyment is completely relative.