Redoubt is not a fun talent at all. All it does it make Shield Spec worth 8 points instead of 3. Remember that there are no crushing blows in wrath so your whole reasoning for taking it is moot. This is the definition of bloat. If you really like it don't make it mandatory for tanks to take it for shield spec. Alternatively make it worth one talent point or something. Prot forums have been whining about this for ages.
I think a lot of paladins are looking at Redoubt through the lens of TBC, and not WotLK. In TBC, because we had to reach uncrushable, paladins piled on lots and lots of Avoidance. This greatly reduced--and eventually obsoleted--the value of Redoubt.
WotLK looks to be different. There seems to be a lot less Avoidance gear. There's even a rumor that dodge and parry rating will see non-linear scaling, like Armor. If you have a lot less Avoidance, then Redoubt still does a lot for you, increasing your block rating significantly. As well, with the new focus on Strength, and the fact that 2 Str = 1 Block Value, we have the potential to mitigate significant amounts of damage through blocking.
Now, I don't know how useful Redoubt will be. It might turn out to be useless. It all depends on how much Avoidance is available in raid content. If Sunwell is any guide--remember that Blizzard had to introduce Sunwell Radiance to keep Avoidance in check--Blizzard will be looking to significantly reduce the amount of Avoidance raid tanks possess.