Kinda missed the topic until now, but I'm obviously OK with it. My thoughts are that some 71-73 verts look OK, some do not with the spoiler(s) and I'm thinking that comes down to the overall decor scheme of the car. I am not a fan of the 69-70 spoilers mounted high off the trunk lid. I do like the Pontiac addition to the one shown earlier in the posting.
I also think its an evolving acceptance thing where in some decades the addition of spoilers is more acceptable and others not so much.
I'm a form follows function guy. If the spoiler adds real downforce and balances out whatever you have going on at the front, then it has benefit. If it's just to look purty, then no, convertible or not.