Personally, I prefer
Liv to
Olive, but I think
Olive can be elegant and also spunky. Someone here a while back introduced me to Olivine "-een", a color name, which I also like. I'm not sick of "-a" endings, as you are, but I agree that
Olive is refreshing, which is why I'd be surprised if it didn't rise in popularity, especially after the fairly recent movie. I, too, enjoy the earthiness of olive, and like olives themselves. I also enjoy the association of the olive branch with "peace". I grew up seeing "Popeye" cartoons, so
Olive Oyl is the only other association I have with the name, but I don't actually think of her when I see the name; I think of "peace".