The entire "western art" discussion in the end boils down "Is it sakimichan_(style) or not?". It's a lost cause, at this day and age there are a lot of different artstyles, some western influenced by eastern, some eastern influenced by western.
In my opinion, another thing to mention is the "elitism" of this site, mainly found in some of it's users and it's rules. One of the rules states that "names should be written in japanese order (surname first, name last)". I've been in the touhou fandom for years, and not once have i heard someone refer to a character by their full name with surname followed by name. This also applies outside of Touhou though.
To search with characters that have their full name as tag, you need to remember their surname first (or type *, but this was a recent addition and not many users, especially "casuals", know about it). This is detrimental both to taggers and "casuals", who apparently aren't worthy enough to have a say.
I also feel like people aren't "rewarded" enough (since some people need also rewards, not just passion, or maybe lack passion completely) to keep tagme or other similar tags "clean", but i feel like this is not a discussion for this thread (altough maybe an addendum about them might fit in the rules?).
I got a somewhat bad proposal that could be refined into something better: a non-linear rating system which is based on boolean statements, namely "Is it sexual in nature?" and "Does it contain nudity?"
That way "sexual" artworks without nudity get properly tagged, and "artistic nudity" is kept separate from sexual artworks.