My preferred type of VN is chuunige, which are generally low on the eros... but the fact is that almost all the best Japanese-made VNs are eroge. All-ages versions come later, if at all (and in extremely small numbers), and generally don't sell well enough to justify their production, which is why they are so rare. The vast majority of non-ero VNs in Japan are otomege, the faux female-oriented VNs that do little but brainwash young girls into thinking DIDS (Damsel in Distress Syndrome) is normal. It takes a very peculiar aesthetic for a completely non-ero Japanese VN to succeed (5pb's two different Science series containing Steins;Gate and Ever17 respectively are classic examples).
A lot of eroge that came over here since 2013, with the exception of JAST's releases, ended up with all-ages versions on Steam, but it needs to be said that the amount of backlash from that still makes me wince (happily, I was playing them in Japanese, so I didn't have anything invested in the explosive arguments involved). Indie (Doujin in Japan) games are the ones most likely to be all-ages, and these games can either be great or pure crap... and the best ones generally never get completed or end up buried in the dark corners of the web.
Fortunately for beginners in the EOP community, there is a decent selection of titles in English with all-ages or low ero versions. However, for those of us who abandoned EO long ago, all-ages is a drop in the bucket, lol.
As a note elaborating on my initial statement, I could do without ero entirely in about 80% of all chuunige (there is always a certain percentage where the sexual intercourse is so interwoven with the story that it stops making sense when surgically excised). However, if you stick to VNs for a while, you'll find it harder and harder to avoid eroge.
As for nukige... it needs to be mentioned that nukige make up over two-thirds of the VN produced worldwide (even if you include doujins and indie stuff and OELVNs) if you count all those made in history. It is a very rare long-term VN player who hasn't at least experienced one nukige.