i would suggest an amulet based defense occult troop, 

a Frost Mage, say its 1750 amulets each . super high beastiary defense

One more suggestion from Jerry

Mongol Cavalry Archer .. Offensive... fast troop

Ok several suggestions from friends in teamspeak.

Jerry:

Basilisk in beastiary... offensive

Hell Hounds in Occult ... Defensive, strong against infantry

Anne

Gargoyle offensive Occult

Minotaur defensive Cavalry

Banshee defensive infantry

Sahira

Gerbils fast infantry unit, able to go where no other units go... ROLF (Offensive)

Gerbil Riders cavalry... the name says it all

Amanda

Miasma, occult zombie lady .... amulet troop defensive better than demon

Talon

Goblin Sapper ... Disables your walls.

Pheonix - Bestiary defense... absorbs fireballs

More spy units. You should be able to make spy units in infantry,cavalry, and occult types.

How about a legendary unit that speeds up troop movement?

Allow players to summon stone wraiths instead of regular wraiths. Stone wraiths can be sent to another castle as a castle guard for 24 hours or one attack-death.

A legendary that increases carrying capacity. 

A legendary unit that increase attack or defense ONLY in battlegrounds. Could be summonable. A random BG legendary every 24 hours? Ability to purchase?

Why new units when there is units that not really worth to use as it is.. Like small fat dwarfes with no real purpose. Some units could need so re-balance to actually be useable. I got a feeling new units of any value will be behind a paywall as well.