Why are there so many moving parts used in the landing gear?
One of the key points (circled in red) above shows the part that locks the gear in the extended position and requires that the linkage up top (circled in blue) is actuated to release the gear. 

At the end of the clip you can see a glimpse of the linkage bar at the top returning to its previous position. That way if the gear is dropped by gravity it will lock itself once fully deployed.

If you strip those parts all that's left is a basic 4-bar linkage and a connection to the gear door.