There will be a cycle of off-color legends.
Akroma, angel of fury - Not sure on the abilities but I think it's uncounterable.
Mirri will be a black cat vampire.
Crovax will be white and have 'white creatures get +1/+1. Nonwhite creatures get -1/-1.
Braids will be blue.
Not sure about the green one.
There will be a cycle of slivers that give off-color abilities (green gives haste, black gives first strike, red gives sac: draw a card).
New mechanic called vanishing which uses time counters on permanents.
There will be suspend cards with triggers on removing a counter, like WX:suspend X Whenever a time counter is removed- put a creature token into play and the actual card is a creature with p/t equal to the number of tokens.
A cycle of multicolour dragons very similar to the invasion ones (6/6 with abilities on combat damage) The Green one has pay 2G on combat damage to put 6 +1/+1 counters on it. Black one has 2B to reanimate a creature.