I love my 11. I also loved my 8+ - great phone. Overall I like the size of the 11, and I really love the camera and the battery life on this thing. The camera is fantastic as well.
I'll second all of this—I always felt the 8/8 Plus cameras weren't as good under certain circumstances as even some prior models (I think the early machine-learning features), and the 11's camera blows them out of the water. I was not planning on upgrading back in September, but I saw the difference for a friend that upgraded and took advantage of Apple's trade-in process.
Will I have wish that I waited for the 12? Maybe? On the other hand, the better cameras have been great, eSIM is handy, and I like the slightly smaller size.
I think there's no right or wrong answer since some people will be happy going SE/6S->12, while others are going to go 11->12 in the fall. If you can find value in some of the additional features, go for it, otherwise there's nothing wrong with keeping an older phone in service.