I mean yeah, guessing actual numbers and proportions is just that, wild guesswork. My point was more that of that 1% that are now still calling themselves High Elves, a disproportionately large amount are Alliance war veterans. Most of the elven units seen in both WC2 and WC3 were volunteers rallying to aid the Alliance despite Anasterians wishes (who opted for isolationism), and were probably more likely to be among those who were not in Quel'thalas when Arthas ravaged it (since they either stayed behind after the second war or once again left to aid the Alliance during the third and ended up following Jaina or such) or among those exiled later (already proven to not be ones to blindly follow whatever the rulers of Silvermoon dictated). Kinda depends on how large the elven force during the Second War was whether there are likely to be many of them left in Quel'thalas and calling themselves Blood Elves these days, but yeah, that's just half-educated guesswork on my part.
Considering so far the only elf with war paint is Alleria with a blue stripe, I doubt they'd want to muddle the waters any further than they already have by making Horde elves look more similar to Alliance elves. Even if they never intended to make High Elves playable giving both sides opposite colored face paint would probably help make it clear if something is an Alliance NPC or a Horde Blood Elf. Or limiting blue to the Alliance ones and giving Horde red, yellow and green, all of which kinda fit various Blood Elf themes more than blue does.