It's really, realy rare that I can get a decent deathstrike off on someone in pvp as it is right now due to the rune costs on top of the disease dependencies.
It costs 1 frost and 1 unholy rune right off the bat to get both diseases going, and death strike costs another 1 frost 1 unholy rune. This means that in a 10 second rotation in pvp, I can either:
1) Apply both diseases and get a death strike off, or
2) Keep my enemy snared via chains of ice (no frost fever) and actually have another unholy rune available for things like bone armor, AMS, or another plague strike to deal with a HoT.
If I use icy touch > plague strike, and death strike at some point in that rotation, I won't be able to use chains of ice (not an option in pvp). If I open with chains of ice, I can't apply frost fever and use death strike in the same rotation. If I open with chains of ice and death strike, the heal is pretty damn weak, so I feel compelled to get frost fever on, but then I can't use death strike at all. It's very frustrating.
I can't use my pvp abilities in the same rotation and expect to use death strike, simply because of the overlapping rune costs. It's simply too costly, which sucks, because I was really looking forward to being able to use death strike in a pvp scenario.
For these reasons, and those listed in the post, I'd really, really like to see death strike be swappable with blood strike in a standard rotation (1 blood rune). You have the option to do extra damage, or to heal yourself. Seems more reasonable that way, especially if you unhinge the OP blood worms from death strike in blood.
There are simply too many dependencies to make it worth while, and then when you get to that point, you won't have the runes if you also need to keep your target snared (which is obviously a must in pvp). The frost rune cost on death strike, if anything, really needs to go. I say blood rune is a good candidate because I often really don't care about using blood strike that much in pvp.
You can watch that pvp video I linked and see how many times I was able to get a decent death strike off. (read: Zero)
The deathstrike (and obliterate, for that matter) rotations work well in PVE because you don't have to worry about using chains of ice all the time, or another unholy rune ability (which a lot of pvp abilities tend to be), simply because those fights aren't as dynamic as PvP fights. You don't have to worry about mobs running away from you (chains of ice), catching Hots (plague/scourge strike), or bursting you down (AMS/Bone Shield/AMZ).
Please fix this.