Same here. Very interested in Postfix 3.X. Dev's please consider.
It's been a deal breaker. In my scenario, I've got several clients that want to migrate out of cPanel and into CWP, yet they do not want their employee's / clients to have to make any changes. A "seamless" migration is what they need, and I agree.
Ever try and walk an idiot through modifying their Mac Mail over the phone? Now multiply that by 100. That's my life. And when something like "mail.xyzdomain.com" was used with SSL, Postfix 2 just isn't cutting it.
With that said, I've got a few test nodes going, and have manually installed Postfix 3. But I'm yet to delve into anything further as installing is one thing, making use of is another...
If anyone has any concepts of making this work sooner than later, I'm open to destroying an install or two. I'm likely on that path to this already (the destroying an install part at least). haha