To be fair there are plenty of ways to use bending in an amazing way. I can think of five different ways to use Waterbending that haven't been in the show.
Actually bending of one's own blood, they don't even need to be a blood bender to do this, the act of just having a cut on your finger and drawing blood from that would be an interesting concept, and the fact that such a simple thing would be able to fix internal injuries if two people shared the same blood type could be amazing.
The use of Saliva and the liquid in our eyes is also never explored, Waterbenders have the ability to make their entire bodies weapons if used effectively and we know bending that comes directly from the body requires little to no movement.
Or how about hollowing out the ends of daggers filling it almost completely with water, (Not all the way, since the water still needs to be able to move and not be stagnant) and controlling knives like that.
Why haven't we seen a lightning bender that uses powerlines and other area's to their advantage?
Why haven't we seen more people that use animals along side their bending, why not have an animal completely immune to fire, that have giant pours. And let itself turn into a giant ball of fire if it swallows a Fire Bender.
There are a lot of unexplored bending potential in the series. Considering this Season more than any shows, that bending isn't completely limited to movement or the rules that have been set up before.