ive got the same feeling that i'll be happier with the IQ , Ive barely used the flip screen except for a couple of Macro shots I dont think I'll miss it
I upgraded from a 40d to the 6D about eight months ago, and I'm very happy. I think the 6D is a great camera for your intended portrait and landscape uses. If you're doing macro, remember the 6D has wifi, so you can use a free app on your phone or tablet to shoot while viewing the LiveView image on your device instead of the camera. I've never had a flip out screen camera, but in my opinion using a remote phone to view is even better anyway. You can position the camera any way you need and still have easy access to the image and controls on your phone. I did not buy the 6D for the WiFi. I bought it mostly for better lowlight, and it has met my expectations. However, now that I've used the WiFi quite a bit, it's something I would really miss from other cameras.
When considering lenses, remember how your field of view will change with full frame. I had to sell my 17-55 because it wouldn't work on my 6D, but I discovered I use my 70-200 MUCH more now than I did with crop. I ended up going with a 35 f2 IS for a wider angle instead of a zoom to take even more advantage of being able to shoot in very low light with the camera and lens combo!