Looking back at the first SDCC and proto pics, the thin fabric did seem to have a really nice and elegant look to it, so I can understand why they might have thought it was a good choice early on. But somehow in hand it just ended up looking a whole lot cheaper and uglier.
The original dress is an abomination. HT went thru a weird "synthetic" phase with Leia's dress, Han's shirt, Luke's tunic -- all had this "parachute" feel to them. Must have been bargain day at the parachute store that year.