I am just theorizing here (not even theorycrafting!
), but shouldn't the new Blood Tap fix most problems? It basically changes the current BT from a static cooldown to a cooldown based on how fast you Rune Strike, and it can be banked on so you can squeeze out a DS even when you are most rune starved. Also looking at Runic Conversion and Lichborn, it could also fix the situation of having to sacrifice DS for other spells (the obvious "dilemma" here is that Conversion can be used whenever but is weaker than Lichborn due to not regenerating runes, however Lichborn is on a longer cooldown, thus a meaningful choice).
The sky might not be falling yet (I was truely excited to see new BT, bankable death runes and no RNG yay!).