e? said:
Yeah, it's definitely easy to tell leeks apart from other long onions; they're way thicker.
The wiki suggests most spring onion artwork is actually leeks, so it might be easier to rename spring onion to leek and sort out the spring onions from the leeks. Or create a tag for all forms of long onion (to differentiate from bulbous onions).
If we just unalias both, the actual posts will still be tagged spring onion. Afterwards, I'll sort them, so it doesn't really matter since I'll review all posts. Plus, the majority of those posts are Miku posts. So they depict spring_onions and not leeks.
(We could indeed separate the long from the short onions, but this doesn't sound natural at all)
Thickness and length are always relative, how would you classify post #354170 for example?
Miku is supposed to hold a (green) onion, so we'll continue tagging it spring_onion (it's still the same word "negi" in Japanese): the two being often mistaken in Miku posts was apparently the reason for leek and spring_onion to be aliased. Shape matters too, and if it was up to me, I'd tag it "green_onion" (same variety as spring_onion, only harvested later). But that would be my inner autism showing up, and fairly unpractical for users.
The main issue being the difference between "tag what you see" and "canon." Or, more profoundly, the difference between "an artist's depiction of reality" and reality itself. In any case, mixing up leeks and spring_onions because we confuse them sometimes, while there's also a good number of times where they're clearly distinguishable, isn't right. (Bring balance to the onions...)
Back to my answer, Miku posts still depict negi = spring_onion. Basically, everything will be spring_onion unless proven otherwise, since most posts are weeb-related, and spring_onion is more common than leek in Asian culture.