Your current spam is...

Mash these keys
A - OB
B - DS
C - HS
D - RS
E - Buffs
G - Dancing
F - B.Rez

You could modify it like this:
A - OBL
B - DS
C - HD
D - Buffs
E - Do Mapped Key Action - Rotate Runic Power Dump

Mapped Key: Runic Power Dump
Step 1 - Dancing
Step 2 - B.Rez
Step 3 - Rune Strike

You might want there to be more than one chance in five for a Runic Power Dump.
But on any given spam, only one of the runic power abilities would attempt to fire off.

Or possibly do a rotation on that key...
Step 1
DK A - B.Rez
DK B - Dancing
DK C/D - Rune Strike
Step 2
DK C - B.Rez
DK D - Dancing
DK A/B - Rune Strike
Step 3
DK A - Dancing
DK B - B.Rez
DK C/D - Rune Strike
Step 4
DK C - Dancing
DK D - B.Rez
DK A/B - Rune Strike