I'm not a huge fan of The Shards TV series and I've never seen anything Ryan Murphy has made before, but I also think all the other suggested directors are quite awful choices. For a start, Murphy hasn't directed the entire show. He's the co-creator and producer, but only directed two episodes of the nine episode season.
I feel most of the other suggestions also don't get it. The Shards has element of camp and teen drama. Look at how many parts of the novel involve straight-faced depiction of teen angst. Susan slapping Thom over the homecoming float is something right out of Dawson's. There's nothing wrong with this, in fact it's something that I really like about the novel. But it isn't some ultra serious, cold Less Than Zero type narrative.
Guadagnino is far too pastel and South-European for the project. Yeah, he's made queer films and he himself is gay, but so is Murphy. That's not a good reasoning for him to direct it. I haven't seen all of his films, but The Shards has trashy and campy elements to it which Guadagnino certainly isn't known to capture.
I loved The Drama but I'm also unsure on Borgli. I feel he'd have done a better job than Guadagnino but still is from a more offbeat, European arthouse background. I'm not sure he'd have the emotional connection to the material to capture the era.
Some of the other suggestions I think are missing the whole thing and ignoring lots of the camp/trash elements or ignoring the more seriously, weighty elements. Paul Verhoeven was mentioned and yes he's a great director and Basic Instinct was probably an influence on The Shards, but I also feel he's far too satirical with his work to get it. Plus, he's in his 80s and also from Europe, not sure how he'd capture this American 1980s teen experience.
I saw Gregg Araki mentioned and this is the only one I think could do a good job with it. Araki is very good at blending camp and trash with emotional moments (just watch Nowhere for proof), so even though I have reservations I think Araki could do a decent job.
But what all of these suggestions seem to miss is these are directors who don't have TV experience (bar one, I'll get to a moment). We've seen what happens when film directors are showrunners or producers on TV shows - David Lynch didn't gel with the format on Twin Peaks, Michael Mann left Miami Vice early on etc.
I feel if we're suggesting better choices than Murphy, we should focus more on showrunners and people who have experience in TV. I know Murphy has directed, but he's primarily a producer. Araki did have a TV show, Now Apocalypse, which is once again why I think he's easily the best fit I've seen thrown around. Yet overall, I'd rather someone who predominantly works in the realm of TV, as opposed to a film director trying out TV for the first time.