i personally love what they did with the necropolis for this heroes! in fact, its the faction i'm currently most excited to play as...well, second to the sanctuary (because they are new)
i think the new design for the liches is awesome! love that they replaced the boring zombie with the ghoul...and the ghost has some pretty impressive abilities for a core unit
the best improvement was made with the addition of the lamasu and the fate spinner...maybe i'm not skilled enough at this game, but i've always found that having more units with the necropolis was never enough to overcome the disparity in physical attributes (attack, defense, etc)...i'm really hoping these creatures do something to balance the scales