Please remember that these are rumors. Some of this conflicts (the special characters part) conflicts with Tastytastes rumors, which in my opinion increases the amount of salt required for this set.
Berserker could be looking at a slight point cost drop, and they cpould have the option for 2 Hand Flamers, plus their Khornate Chain Axes could possibly give a re-roll to wound.
He has implied that Defilers will get better and be upgradable.
there will be "lots of "New" special characters ranging from bikers to (possibly) a dread and quite a few Terminator Armored ones"
HQ selections moving units to different FOC slots.
we could see Thousand Sons Psyker Dreadnoughts, Flank Marching Alpha Legion Terminators and Iron Warriors Havocs with "Tank Busters" rule.
Cult units to all have a list of upgrades such as Bikes, Wings/Jump Packs, Terminator Armour etc. Whether this made it through development, we'll have to wait and see.
There was also a strong implication that the following could be army-wide special rules for specific Legions:
*Iron Warriros: Tank Hunters
*Alpha Legion: Infiltrators
*Night Lords: Stealth
*Word Bearers: Stubborn
*Black Legion: Re-roll all failed LD tests.