After reading a comment on one of the DK applications regarding RP usage on blood ill clear the following:

Runic power mastery blood build is a known viable build for players who struggle with RP.

Blood is actually very RP demanding since you do need to dump quite frequently in order not to waste GCD
and DRW needs 60 available RP to use and while you are trying not to waste GCD you might get into trouble poping DRW with optimal conditions.

Often you have a situation with all runes on cd and blood tap is also on cd.
You won't use ERW because you should save that to when DRW is up.
Also, you might be stuck with low RP and a DRW cooldown with 10 seconds left.
You will then need to build to 60 RP (unless AMS can be used), but then be left with most if not all your runes on cd, again.

Now, I'm not saying Runic power mastery is a mandatory talent to pick with blood, but it can make life easier.

DRW can be a huge dps boost if poped with ideal conditions, and can be shitty if poped with less ideal conditions.

Making life easier for yourself will never beat out 3% Strength.
Yes Blood with Runic Mastery is a viable build, but so is 0 0 71, it'll get you some dps, but you'll always be beaten by people who've specced properly.

Edit: Forgot to mention, more runic power would be nice, if the runic power can go up to 140, not just 130, having 130 runic power gives you almost the same options as having 100. Either you use DRW and DC or DC and DC, all 130 gives you over 100 is being able to go DC DC DC which no blood dk should have the gcd's to do

As I said, I don't think RPM is a good choice, especially not vs 3% str.
but 130 grants you to DC - DRW incase you have a GCD to spare before runes start to go active.

In a good blood rotation you should be able to perform DC DC at worse case.

Just a reminder of optimal DRW conditions:

1. ERW off cd
2. Hysteria
3. Trinkets or procs
4. Full death/blood runes
5. Blood tap off cd

And of course IT and PS should be the opener of DRW since it cannot benefit from your diseases.

Am I the only one that would time end of DRW with AMS to do a DC spam while all my runes came back up? Been a while since I did the whole blood thing tbh.

Im gonna have to side with Ell on this tho... viable doesnt mean optimal and 3% str is just too good to pass up, I tend to prefer flat increases tho so that might affect my judgement .

Viable means can output competite dps to other similar builds with similar stats.

RPM is just a talent.... you know you can get RPM and the 3% from unholy, and let go the blood caked talent.
I don't have access from work to all the WoW-Lore, but as far as i recall, high gear (mostly 251/264)
favors 51/0/20 builds and variations without a single point in frost tree.