Well you have already had an anniversary money building so that wouldn't be original. Please don't give out another anniversary unit either as that doesn't really do much for anyone. How about hold a PVP goal event for 7 days during the holidays that requires a player to complete 2014 attacks (not raids) to ring in the new year.
Upon completion of the the goal, the player will unlock a new boost building from the store. The new boost building will provide a 20% attack boost (when fully upgraded to L10). Since everyone is already heavy in defense it's time to offset that with some additional attack.
Get your programmers in gear and let's do it.
Happy Holidays!
Evil M.