In the newest developer diary featuring class changes and additions in Mines of Moria, the creation of the Warden is discussed in full.

When I was first asked to lead the design for one of LOTRO’s new classes I was given two main directives. The first was that the new class should be able to function as a main tank in grouping situations, and the second was that the new class should be visually distinct from all the other classes. Those goals, along with the class name formed the foundation of the Warden.

For more information on the spear-wielding class, including an in-depth discussion of Gambits, which are special combos of skills, read the diary entry.