Is it possible to have a good Let's Play of a Visual Novel?

Sure. Why not?

Game, set, match motherfucker.

But really, it comes down to personality. If you can spin a joke really well, then there's loads of material in visual novels ripe for making fun of. MetaDating works because of the hosts mostly, and in this one it only helps that it's Hatoful Boyfriend. It might not be the best idea to start out LP'ing with visual novels, though...

I think it depends on what you're looking for in a Let's Play. What constitutes a good LP? I think it's not easy to answer this question.

Would be funny to see someone play School Days and get one of the bad endings, although there would be those awkward moments.

Only if the hosts get the tone just right like Jeff and Vinny, otherwise 90% of the time it's probably best to leave it as a long play.

I think it's possible but really hard. A few key things you need are: A group. One guy can't easily carry such a time consuming and low profile experience. You need interest and or investment in the story or characters (alternatively you could just ridicule it for entertainment, I GUESS). If you don't care, then why would the viewer. Let's players influence the viewer's opinion way more than either side cares to admit.

So basically, bring a friend or two, make sure everyone is into it and make sure you have some stuff to talk about inbetween. Voicing the dialogue by assigning characters could make a big difference too.

I think Day9s series when he plays VNs with some other guys are fairly entertaining, they could be a good reference point.

And for the record, I think Persona is WAY, WAY more suited for let's plays then a run of the mill VN. Persona breaks up the pace and the actions in lots of different ways and requires more player input. It's a game while VNs are more like books.

If you want to watch someone click X for a bunch of the game, then Persona 4 fits right in.

I like visual novels, but no, a quick look would only be entertaining with specific people for specific reasons for specific people, like me. It would be about as boring as "shooter X" quick looks are to me for everyone else.

Edit: by quick look, I mean let's play. I had Giant Bomb on the mind for obvious reasons. Basically what I mean is that you'd be appealing to a niche within a niche. I'd rather experience a visual novel in silence even if through video. I did happen to watch a little Virtue's Last Reward let's play action before the game had reached my door because I couldn't wait any longer, but I was constantly irritated by the commentary.