[Kintarooe]

doing some math :
average hit Sb 3k - cast time 2,5 second
average tick corruption : 400 - cast time 2 sec (x 6 tik).
Dps is still equal for time of cast but sb 1 time to 3 is a crit.
for example ... think about a circle of casting with corruption and no.
1 corruption have 18 sec duration + 2 sec initial cast = 20Seconds
I count all Average hit/tick that gains debuff, buff, elixir... (at the end of the raid) ecc.
Case1 (corruption + spam Sb with 202 hit rating and 33% crit).
2 second cast Corruption = 400 x 6 tick = 2400 after 18 seconds.
left 18 second / 2,5 sec cast Sb = 7 cast of sb
7 cast at 33% crit are 2 crit and 5 hit (average)
2 crit = 12k and 5 hit = 15k
then 12 + 15 + 2,4 = 29,4k in 20 seconds

Case2 (spam sb with 202 hit rating and 33% crit)
20 seconds / 2.5 cast = 8
8 cast at 33% crit are 2 crit and 6 hit (average)
2 crit = 12k and 8 hit = 18k
then 12 + 18 = 30k in 20 seconds

then, with average hit/tik , 1 cast of sb is more efficency than 1 cast of corruption (for a 0/21/40 build).

all imho :D