i find it's a lot less annoying if you simply call them "senryu"

Definitely better, although there's no obvious way to map on to English. Using morae works OK, but most non-linguists don't even know what that means, much less how to count the morae in English phrases.

i'm not entirely convinced basing english poetic constraints on morae makes sense. for faux-senryu in particular, i've found that simply sticking to 5/7/5 syllables, coupled with a good feel for the rhythms of english speech, produces very pleasing results.