I finally got around to upgrading my gear from the old 346-359 stuff to the 378 gear that drops from the new-ish Dragon Soul dungeons. However, my DPS has gone from fairly regular at 11-14K (depending on encounter, Avenging Wrath use, procs, etc), to being all over the place. One mob I'll be at 12-13K, the next I'll be at 24K, then down to 9-10K. I'm not changing my rotation, and I don't notice any major slowdowns or other issues like stuns. My normal rotation is something like:
Judge<CS<Holy Wrath<CS<Inquisition<CS<Judge<CS<Holy Wrath
(using Art of War and free Templar's Vengeance procs to cover dead time whenever possible, and keeping Inquisition up at all times)
You don;t really want to be sitting on your procs to cover dead GCDs, nor should you be alternating CS with other abilities (until you get CS down to a 3s CD). Instead use a priority system for your abilities something like Inq > CS > HoW > Exo > TV > J > HW > Cons
Prot will cycle CS every other strike but ret loses dps to do so. Ret is basically still first come first serve except there is a much more pronounced importance to clash resolution.
There are quite a few web pages out there that cover the priorities for clash resolution and it changes based on your gear with T13 bonuses. The addon clcRet will get you REALLY close to optimal rotation and the better you are at configuring it, the better it is. Without T13 bonuses, it should be pretty spot on out of the box.
Don't worry about your CS cooldown time. There is not enough haste gear in the game at the moment to get it to 3 seconds which is the only break-point that would matter. Go with Landslide, it is definitely more dps.
Also, Inq should be used with 3 holy power and preferably less than 2 seconds left on the existing Inq. Unfortunatly, that won't fall into a consistent spot in a "rotation". Don't waste holy power by holding 3 hp with a few seconds left. Either practice enough to know how long it takes you to get 3 hp and make that your minimum duration remaining on Inq to pop it again or when your gear and rotation are good enough, it is safe to let it drop a second or two so you don't pop it "too soon".
For instance, without T13 2 piece, it may take you 6-8 seconds to get 3 hp. When I was there on my gear, 6 was my number. When I hit 3 hp, I check Inq. If it was 6 or less, I used Inq. If it was even 7 seconds, TV and keep going.
With T13 2 piece, judgement gives you 1 hp. Suddenly, you have TONS of hp it feels like. Move judgement up to #2 on priority, right behind CS and now it is safe to use the 2 second check on Inq.
Note: Even though I called CS #1 and Judgement #2 here, make sure you read the info on ret. They are top priority assuming you are not wasting any hp to use them (i.e already at 3 hp).