I must admit I like the “old etymology” better — one of “discarding what is bad”; and it is more closely related to anapana.
So, “passa” here is not the same “passa” in “assa / passa”?
And “vi” means different things in different places too, I suppose? In vicikiccā, you explained “vi” as “twisted”.
“vi” (twisted) + passa (assa/passa) would actually make a good combination: discarding what is twisted. It brings the point home better than “special seeing”.
Anyhow, just some musing; a word is what it is despite my liking.