TBC Liadrin might have been interesting, but now? Not so much.
Like in D&D it's very hard to make paladins interesting, and arguably they're the most interesting when they're kinda fanatical, think Scarlet Crusade.
So no, the game isn't better when she's at the forefront, but then, neither is it when literally any other paladin or priest is at the forefront.
I think you're ignoring the fact that Priests balance the light and dark more than any other class in WoW.
Truly, we, are the ultimate class.
"A flower.
Yes. Upon your return, I will gift you a beautiful flower."
"Remember. Remember... that we once lived..."