Wardens have their roots in the art of healing, but over the years have focused their abilities on buffing and fighting. They retain the ability to cast basic heals, but are not as strong of a healer as they are as a fighter / buffer.
Wardens can train in one hand weapons as well as parry and are able to wear Scale armor and use a standard medium shield. They also have the ability to use a short bow. This gives Wardens a good foundation as a fighter, but their magical abilities are what really give them their real power.
Wardens magical abilities focus almost exclusively on buffs. This includes the group effecting damage add, run speed, and bladeturn chants. Wardens also have group castable resistance buffs and several stat boosting buffs. Wardens also have several self-only buffs, including the best haste spell in all the realms.