Here is my wishful thinking on what might happen if we are lucky.
New Turn Evil Glyph - who knows, it might not even be a Turn Evil glyph any more at all.
New Ret Passive:
Angelic Tongues - Teaches the Paladin the sacred language of the realm of light, allowing auto-attacks and movement to occur while casting.
This would allow us to use Repent, Turn Everybody, and Flash of Light while moving, and without resetting the swing timer. We have no other spells with cast times other than Redemption.
I would happily take a small Flash of Light nerf of lets say 10-15% if it is needed for balance purposes. Overall, I just really hope that Blizzard does not have the audacity to put 2 talents in the same tier that are only good for Holy, Repent in its current state is already a slap in the face, as it takes a classic Ret ability and makes it almost completely a Holy spell, it would be outrageous if they remove Burden of Guilt and replace it with another talent option for just healers.
Edit: one option for Glyph of Turn Evil I can think of is this actually:
Glyph of Turn Evil - Your Turn Evil spell is now instant cast, but your casting speed is reduced by 10% for 8 seconds after casting Turn Evil.
Edit 2: Come to think of it, do we even have confirmation that Turn Evil will have a cast time at all in 5.4? It wasn't really specified in the notes. Another thing to keep in mind is that Blinding Light shares diminishing returns with Fear rather than disorient effects, so for holy Repent would still allow longer cc chains, as Turn Evil is of course on the fear dr. In addition, Repent keeps people still for Holy to walk up to and blind, if someone is running around in fear chaining Blinding Light will be quite difficult.