My AGV Sport is vented and I haven't been hot wearing it zipped up. As long as I've been moving I've been relatively cool. Last Saturday it was 104 deg F and I felt that the jacket actually insulated me from the heat. But out here there is no humidity so that may play a factor. Also, had to send in my AGV to get a zipper fixed and started wearing my old black unvented leather jacket and that thing does get hot.
Maybe it might not be a bad idea to check out the new technology in modern jackets to stay comfortable and protected in the heat. In my opinion they work.