imsodark

No, you're not the only one. I also wrote it previously that i dislike her obsession. It's just annoying and not fun at all.
Fan-disc is a sore spot for all Tsujidou fans here.

lots of hate? apart from the translation of the secondary routes, it's one of the best (imho, THE BEST) VN ever.

Anyway, I suggest you to play Noble Works.
Good story, great characters, good artworks.
I like it almost as much as I like Kono Oozora.

For my money, Wagamama High Spec and ChronoClock were both solid VNs that fit your list of preferences perfectly. You'll probably love Princess Evangile (link NSFW), though I didn't much care for it. That said, you should really refer to this thread:
And consider broadening your horizons and trying something outside slice-of-life. Your stated preferences are definitely ideal for getting the most VNs in terms of quantity, but the best VNs tend to be the ones that step outside that mold a bit. Maybe give Gahkthun of the Golden Lightning a look (the MangaGamer release [NSFW link] is exactly the same as the Steam release for Gahkthun, IIRC).

One quick google search and you'll get the 18+ version with no issues
 

I second this. This is my first one and it got me hooked on VNs even though there are no lolis here. There should be a fan TL of the 18+ version.
Don't expect too much though. Expectations ruins your experience.

Clannad is probably right up your street. Has some moments that will hit you emotionally, like a truck.
For something pretty lighthearted (and VERY lewd), check out Wagamama High Spec https://vndb.org/v17823 . Awesome art, cute music, and a ton of fap material.
 
Now I've yet to play either, but if you want pure engaging plot, check out Steins;Gate and Fate Night Stay.
Since you liked Kono Oozora (I loved it as well btw), maybe check out Dal Segno https://vndb.org/v17742
Also, the ONLY reason I'm not playing G-senjou no Maou https://vndb.org/v211 right now is because +18 version hasn't been released yet. This is one heck of a crime thriller apparently, and I personally can't wait to play it. One youtube video even described it as the 'Deathnote of Visual Novels'.

This one will change your life:
https://vndb.org/v13259

There's Clannad that fits for everything, exccept of the graphical side ( I mean, it's not bad if u get used to it, but the way the characters are drawn is rather... different). It's pretty much the definition of slice of life romance set in school, and is one of the longest VNs out there, has no 18+ content, though (which shouldn't be a problem, since you didn't specify that)
You could also try Maji de watashi ni koishinasai. It doesn't have that much of a deep story or anything, and is more a comedy than anything else, but it also fits your requirements. You're going to have alot of fun if you try this one.

Well I would first say check out Sharin No Kuni since it is very similar to Grisaia No Kajitsu
I would also check out Clannad and Little Busters since they have a ton of slice of life

Clannad as mentioned before as well as The Devil in G-String come to mind. You could also continue the Grisaia Series. 

Maji de Watashi ni Koi Shinasai!

If you like Konosora, then might as well recommend Miagete here because compared to Konosora, the translation was already improved or so that's what I'd heard. For other VNs, then perhaps you could try HatsuKoi and Koichoco. Hope the recommendations here would be help.