So, I think the major concern with the new DoT effect on crits from certain abilities, is that if we crit again right away, we'll lose out on a large chunk of damage, as compared to crits which are instant, and Divine Storm doing holy, which is, again, instant.
With the new DoT being our compensation for the DS nerf, as well as a replacement for extra crit damage, it's going to be something we really need to be competitive in PvE DPS, but over-critting will make it significantly less useful than the old setup. Ret can't afford a PvE nerf, period.
Crusader Strike, is also in need of a secondary effect to make it more 'fun' to use.
My suggestion: Add the following secondary effect to Crusader Strike -- Consumes any damage over time effects you have on the target, causing them to deal all of their remaining damage instantly.
Why? This has two effects, one, it prevents over-critting from making the DoT useless, as you'd be getting the full effect of the DoT at least once every 6 seconds. The second effect, is that it synergizes with Seal of Vengeance/Corruption, but because it consumes them, it requires you stack them back up, which would probably put SoV back into competition with SoB, because let's face it, not everyone wants to cut themselves to do DPS.
The only immediate downside I see, is that I'm not sure the code exists anywhere in the game to track how much damage a DoT has 'left' based on the duration. This might be a little hairy to code. Also it might put too much burst back into place, because you could potentially apply the DoT and then consume it within your first cycle, some preventative measure would have to be in place to prevent that.