There are actually several combinations of legendaries for retribution paladins that do very similar DPS (within plus or minus 2%):
And I'd have to try it again, but I think you can even get away without the chain in some combos, but it does tend to be the best legendary in most setups.
The important thing is that you make minor tweaks to the rest of your gear to maximize each setup, which our optimizer will do for you.
You could really go with whichever setup you prefer out of those.
Stacking crit+haste through the roof never seems to get max DPS in my tests, at a point you want to balance it out with some versatility. The optimizer handles finding the optimal "tipping point" for you.