I occasionally go through these thought moments, have an interest in wildlife and no matter how I look at it the 7D is still the best body for me. There is no perfect lens and body its all about compromise, but I forget all about it when I start snapping.
There is a fair bit more you can extract from the sensor with post processing and its easy to over complicate things.
The 6D is interesting as I could often use a second body with a more wide angle and it does get annoying changing lenses. The single cross focus point is sufficient for that, I guess they are trying to differentiate between the different bodies. I can see that I might get one when the prices start dropping a bit. I nearly bought a second hand 50D for that reason, now that I can get ff I might go for one.
But I am also seeing where the mirrorless stuff is going. Some exciting times coming up.
Reading your posts from the start I think you have room in your kit for two bodies, consider the 7D now as its very good value and then add the 6D later as it becomes cheaper.
You mentioned the positives for the ff bodies, but the reach from a crop sensor is hard to beat for wildlife photography, so just consider both.
Comparing Nikon, Sony and Canon is always nice, but depending on where they are in the model cycle they are all leading at some point. I also think that when you look at the features and functions, most of them are nice on paper, but are less relevant in the real world, at least in my world

. Arguably both Nikon and Canon have had bodies that are more suited to normal photography at different times and most of the added features become less relevant, I don`t think there is anything wrong with the back to basics approach. I want to take photos as a main and not drive a computer.