My main fear is that GW are really into looking at their early unit visions over the more modern concepts. Reference daemonettes, bloodletters, even the older style weapons on CoK and reintroduction of the older style helmets in the same box. Also, the less uniform chaos knight models compared to the 6th edition ones.
Regardless of whether they keep the sword axes or not, I'm sure the armour will become more stylised and less generic than it is now. The cool sculpts and distinctive weapons make them look great, but the armour is 'anonymous elf' really.