Okay, I might've seen it here: The Light and How to Swing It: New talent system changes for melee paladins
I know its not exactly an official source...
Quite apocryphal. The writer is obviously conflating things (s)he has read, possibly on these EJ forums. Blizzard has yet to state anything regarding Ret Paladins and Haste. Nothing.
They have mentioned Rogues and Druids explicitly regarding Haste->Energy conversion (as energy->damage). We have theorized here on EJ that for Warriors it would involve Rage (as Rage->damage) increases via Haste (possibly faster autoattack with normalized Rage would alone solve their "problem"). We have theorized that for Ret it would be one of two things - either mana will become a tight resource and Haste would mobilize Haste->Mana (and Mana->damage), or mana remains relatively easy with a JotW mechanic and the next logical option at the time was reducing cooldowns so Haste->More attack (and More attacks->damage, naturally).
With the addition of new abilities to Ret (namely HS and possibly 2 more damaging abilities) I would label reduced cooldowns unlikely. If you have up to 8 buttons to press, and not enough time to press them, you focus more and more on the best attacks. Reducing cooldowns means those "best" attacks are used far more frequently and the "bad" attacks are shouldered out. A side effect is "ZOMG, ability X sucks, we never use it, why do we have it" forum posts. Cue the rollercoaster as it is (unnecessarily) buffed and nerfed over multiple patches.
To explore, I just modeled in my spreadsheet a pretend scenario where haste reduced ability CD in Wrath for my character. I wouldn't use Exo at all and Consecration would be used ~every 40 seconds, simply because CS, DS, and Judge are spammed so frequently. CS is literally every 2nd attack (less than 3 seconds). It's not a great gameplay decision and doesn't add "fun."
Closest cooldown option I could see would be reduction in GCD (not just for spells). I won't even conjecture whether that could find a happy balance point.
Blizzard will unveil some useful mechanic for Ret haste when they have one that works.