Uhhhhhh...I'm torn between answering the question or wondering if it would even be worthwhile to do so, since there's a couple of odd assumptions embedded in the query...oh heck with it.
No, the original VN does not "undermine" the artistic value of the franchise. It's the
best expression of the franchise. Whichever anime you watch, you're only getting at best 1/3 of the story in total, no anime has yet adapted the best of the three game story routes, and they've all been flawed at portraying the major themes (especially when it comes to Shirou). I'm hoping the new Ufotable anime will rectify that a bit. Note that I'm not talking about Fate/Zero, that's a separate thing (it's adapted from a light novel, not the VN).
The adaptations are hardly "heavily" censored, for a game that's 50+ hours long, with seven sex scenes between 4-10 minutes long each (depending on reading speed), most of which are in the currently-unadapted route.
...okay, to cut it short, I'm assuming you're asking "are these anime associated with porn, and thereby tainted irrevocably," to which I'd say "no, but it wasn't even tainted in the first place." Fate/Stay Night handles sex pretty well for its story ('cept maybe in writing quality, but that's a different conversation). In fact, being a consistent prude is a pretty bad thing if you consider Kanon to be an equivalent comparison (I played the original, adult version; Fate/Stay Night's scenes had to be replaced, but Kanon's sex scenes were pretty much designed to be dropped like a hot coal).
[Kira Must Die said:
]I haven't read the visual novel, so I can't say how relevant the sex scenes are in there, but watching the anime, you never really get the impression that there was suppose to be sex scenes. It never really feels censored nor does it really feel like it's missing chunks of story. The story seems intact, although I'm sure VN purists would say otherwise.
The story's perfectly intact, just missing the cuteness of one particular scene ("I can't return your feelings," huh, Saber? Riiiiggghht...), and arguably worse for having a Mana Transfer Dragon (though it replaced the threesome, so I guess it's a toss-up). And the UBW movie was endlessly enriched for including the dolphins instead of Rin's sex scene.
Bara_no_Hime said:
Also, I thought the next Fate anime was supposed to be Heaven's Feel! I feel robbed. Robbed and cheated out of Sakura Awesomeness.
If those other people are to be believed, our Sakura will take the limelight.
And when it happens, I hope they'll at least keep the sex scenes (at least one "mana transfer" scene and the "why don't we bang just because we're into each other?" scene) and just compromise by having them offscreen. I really do think the story loses something important when it replaces them with Sakura just drinking Shirou's blood every so often.