Great news!
Honestly I never really bought the Hal/Pine rumors as I think Green Lantern is a little too close to Kirk/Trek. I mean Pine is already starring in one space adventure series, hence I don't think he'd be thrilled to do another one.
But Steve Trevor is something different, and I definitely think him and Gadot look good together. Since they are using Steve there are two things I really hope they emphasize with the character:
First that Steve Trevor is a hero in his own right, he might not wear a costume but he can kick butt when he needs to (he is NOT a wimp, or a bumbling buffoon).
And second, that they make it clear the reason Steve is attracted to Diana is BECAUSE she is better then him. He is a guy secure enough in his own masculinity to not feel threatened by Diana, but to actually love the fact that she is a bigger bad*** then himself.
If they manage to hit those two points, then I will be one happy fan. Steve is too often overlooked or written off as a loser by some fans, I really hope they remind everyone how great a character he can be if written right. And I have no doubts that Chris Pine can do Steve justice.