This is old news and unfortunately all intentional in SE's design. I actually made a rant thread about this back sometime last year when PVP first opened. All this "delay" you guys are mentioning here has been going on since day 1 since PVP's inception (actually since the game launched for PVE content as you have seen with Benediction and Hallowed Ground but happens more often in PVP because ALL the PVP skills have unnecessary, cutesy, carebear animations to appease the eye-candy kids) of it in December of 2013. It's just that since you guys are just getting into PVP, you're seeing the fail of SE's location engine and animation delays for the first time in fast, high-paced action situations all in its abysmal, failing glory. it is a slow-responsive game trying to deal with fast-paced player reactions. It is not latency, it is a delay caused by stupid animations that 9 times out of 10, no one even sees, and you die in the animation which makes your spell go on cd AFTER you're already dead.
My only suggestion is to cast your spells early. DO NOT wait until you are near dead to cast them because you will die in the middle of doing your stupid kung fu animation and your skill will still activate after your corpse is already rotting on the ground and will go on cd. PVP Skills that are affected worst by this delay because they are "OSHIT" (I'm getting pain-trained) skills are Attunement, Purify and Equanimity, PVE spells that already had this delay since game launch are Benediction and Hallowed Ground. These skills are most adversely affected by this delay because they have "long" animations and are mostly used in emergency high damage situations where you or your target are more likely to die if you don't use them. It is not something SE is going to "fix" because in their eyes it's not broken. it is all in the game's design intentionally and it sucks because other PVP games I play, when I press a spell, it happens, instantly, asap, and there is no delay like there is in this game. Fail.