Re: Diana's costume: I really liked Darwyn Cooke's take on it in The New Frontier. Basically the same, but with an armor skirt instead of hot pants (pteryges, you called them?), like a Greek soldier.
Re: Amazons and technology: I'm not sure, personally, if it would have been feasible for them to reach industrial-level tech, but yeah, they should have known the plane was a machine.
I like Steve Trevor. He doesn't have to be Diana's love interest, but I wish he were a more visible part of her supporting cast these days.