@egreg: To risk the war ... (
tex.stackexchange.com/q/28836/86), I use the
\coloneq(q?)
quite a lot but I
also back it up with words. When scanning a text, I don't always see every word but the
\coloneqqqqq
stands out and says "here's where it was defined". Then I read the surrounding text to reach enlightenment. So there's a place for symbols, but I agree that they should not
replace the text.