You're also reading Eustia right now? Neat, I am too (though I'm reading the adult version).
According to pretty much every review of it I have read, you should read Dies before Kajiri Kamui Kagura. They're directly related not just stories set in the same world. Both of them are also supposed to be incredibly hard to read (though you might already know that), basically pretty much the most difficult works you'll find in the medium, along with things like Muramasa and Asairo.
White Album 2 is supposed to be really good (one of the highest rated VNs on erogamescape), Golden Sneer's reviews are a pretty good if you want to know what you're in for. It's still over my level though so I can't read it yet.
Also if you want tips on good VNs available on Vita (well psp but you can download them) I'd suggest Shiei no Sona-Nyl (haven't read it but I've read other entries in the series it belongs to) and Utawarerumono.
Other famous stuff missing from you list are Saihate no Ima, Akagoei, Cross Channel (though the port apparently includes tons of awful extra content not written by Romeo),
The most well regarded VNs on your list are Ruitomo, Oretsuba, Steins;Gate, F/SN, Grisaia and WA2 btw.