Is a Champion a good tank?
The Champion class is NOT a good main tank. If you compare a Champion with a Guardian or a Warden you'll find one or more deficits. The average Champion will have lesser block-, parry- and evade ratings, lesser critical hit protection, lesser damage reduction, lesser incoming heal, lesser skills for survivability and poor skills to get and gain aggro.
But a Champion can get used as main tank. But that highly depends on the skill, experience and equiptment of the Champion, the instance and the other members of the group. I did quite some main tanks runs with my Champion and i have also a Warden. If a rate the difficulty of instances/encounters with my Champion as main tank:
- Sammath Gûl: not easy but ok
- Halls of Crafting: quite difficult
- Great Barrows (Thadur/Sambrog): hard
- The Blind One in Dar Narbugud: very hard
- Durchest in Barad Guldur: is nearly impossible
and compare if the with the difficulty rating for my Warden:
- Sammath Gûl: easy
- Halls of Crafting: easy
- Great Barrows (Thadur/Sambrog): not easy but ok
- The Blind One in Dar Narbugud: difficulr
- Durchest in Barad Guldur: hard
It obvious that tanking with a tank class is just much easier.
The Guardian class is the most effective tank in LOTR: Online. They don't typically burn through as much health in exchange for damage. A primary function of this class is crowd control which is necessary for tanking in a fellowship.
Champions are considered more of an off-tank and are generally thought to be the best soloing class if you plan on adventuring alone. They have some tank-like attributes but not as many as the Guardian class. Additionally, the Champion class does not have any adequate crowd control skills.
There is a lot more information about classes on the LOTR Wiki. Here are the links to both the Guardian and Champion wiki pages:
Guardian Class Information
Champion Class Information
After the Helms Deep expansion (and complete redesign of the class system), Champions are now intended to be legitimate main tanks, if built that way.