Here's my analysis of the new rotation, and why it just doesn't work. There are four main pieces to the rotation:
- Blade of Justice - 10.5s cooldown, +2 holy power
- Crusader Strike - 4.5s cooldown, +1 holy power, 2 charges
- Judgment - 12s cooldown, +20% damage to holy power spenders for 8s
- Templar's Verdict - costs 3 holy power
To the previous paradigm of generating and spending holy power, Legion adds this concept of a Judgment "window". You want to Judge and then squeeze as many Templar's Verdicts in those eight seconds as you can. The Ret paladin mastery emphasizes this as well, increasing the damage done by spenders in that window.
The first problem is that there are simply too many levels to Ret now. You have to track your cooldowns, your total holy power, and the Judgment window.
The second problem is that the cooldowns for Blade of Justice and Judgment are slightly off. Judgment is 8 GCDs, and Blade of Justice is 7 GCDs. So they never quite line up, and are always changing position in the rotation relative to each other. This makes it impossible to really get into a rhythm.
The third problem is that Judgment changes its traditional position in the rotation. Ever since Vanilla, paladins open the fight with Judgment. It's the only ranged ability as well. But now you want to delay judgment until 5 holy power has been generated. It's not really an issue on long fights, but it's very annoying to have to hold off on the ranged ability when going to attack something new.
Even Holy's combat rotation is better, simple as it is. There the Judgment window improves Holy Shock and Crusader Strike. So you Judge as you run towards the mob, Shock, and CS as you get into melee range. It works intuitively and smoothly. (Also, you get to use Consecrate as a regular part of the rotation, which is always fun.)
I gather Blizzard is enamored of the Judgment window, seeing as it's also the new Mastery. My suggestion would be to smooth out the cooldowns by increasing the Blade of Justice cooldown to 12s (increasing the damage done to compensate). The heart of the Retribution rotation would become Judgement - Spender - Blade of Justice. That common piece would anchor the rotation, giving it a regular rhythm that you always return to.
This simplifies the cooldown level, and allows the Ret paladin to focus on Holy Power and using spenders in the Judgment window.
The new Retribution rotation reminds me of one of the Jedi Sentinel rotations in SWTOR. It had the same concept of cooldowns, generating and spending resources, and a damage window. But it simplified the cooldown and resource levels, allowing the player to focus on the damage window.