"I do not suggest a particular Hebrew pronunciation behind IAOUE, but
in the light of the different ways patah and shewa were rendered in
Greek, the antecedent of IAOUE could even be YEHOWA. I mention this,
not to argue for a particular pronunciation, but to show the great
difficulties for a reconstruction of the pronunciation of the divine
name also in Greek."
This argument would only be valid if you assume YEHOWA with a final
patah. But patah is never word final, and so YEHOWA would have to end
with a qamets. Rolf did not give data for qamets, but I would be
surprised to see qamets rendered by E.
If the original pronunciation was YEHOWA, would one not expect to see
sometimes a consonantal text with a mater YHWWH?