again, what exactly did you miss?
what you said sounds more like a "ah other people don´t like the 6D so i get a bad feeling from using it" syndrom.
why would you prefer the 5D MK2 that, overall, has no better image quality?
and at higher ISO the 6D has an edge.
you don´t care about AF (my biggest complain about the 6D) and they cost the same (at least here).
sure the reduced x-sync sucks and the viewfinder could/should be 100% on such a camera, but then the 5D MK2 viewfinder is not much better.
but you get GPS & WIFI, more FPS, better pushable RAW files (less shadow banding), it weights less, has a longer battery life (same battery but it lasts longer. at least without wifi and GPS enabled), better LCD screen, startup time is faster, less shutter lag, CA correction, better exposure compensation and control, full speedlite 600EX-RT Control.
and an electronic level, something i find very usefull for night shots.
I'm one of those who is rooting for the 6d have used it and amazed by its quality but a second hand 5d2 will always cost less.The 6d justddoesn't inspire confidence that my 7d does that was the very same reason I bought it over the 5d2 . So u can understand a 5d Mark 3 is all I need and more but money is a big constraint .I need good lensesmore than anything and can't really decide about selling my 7d