Pondering on it, I think that something else that ultimately clinched my return to 40K was the opportunity to play Unbound lists. Unbound would have made such a difference to my enjoyment of the hobby over the last few years because ever since I came back to playing the game in about 2007 I have felt stifled by the regular force organisation chart. I could never field exactly what I wanted to play.
Unbound basically lets you turn up with whatever you want from your collection regardless of any sort of force organisation, although despite not finding it in the rule book I assume you still need to have a War Lord. It is sort of Apocalypse light and best of all, though some may disagree, it is a legal force to play against a regular FoC list.
My new Death Guard and Nurgle Daemons army that I am slowly building is unbound but I'm not taking the Micheal with it. My lists will still be something recognizable as a fair list. Unlike my nephew who wants to field a pure dreadnought or devastator squad army for his Blood Angels. That to me is crossing the line because all he wants to do with it is win, with no interest in there being a fun game for the opponent. That is the problem with Unbound. If one player uses it purely to win at all costs then there is a problem. Is this something else that Games Workshop hasn't properly play tested and balanced out?
I'm hoping that unbound takes off but in a nice way.