I most certainly would not attribute Fnatics recent slump to Pronax's form (or lack of), Fnatics issues were more to do with Olof cooling down and not posting such huge numbers every game and often putting in shocking performances, JW being massively erratic in his efforts (he has been really hit and miss for a long time now) out of them all Flusha and Krimz have been the only ones performing solidly.
I'd say these two primary factors (Olof and JW slumping) lead to the downward spiral which further contributed to a massive lack of confidence going into the major.
Mixing up the calling didn't work, mixing up the game play didn't and thus the easiest thing was this roster change.
TLDR Olof, JW and Pronax not being on form, change is good to freshen things up!
I'd say these two primary factors (Olof and JW slumping) lead to the downward spiral which further contributed to a massive lack of confidence going into the major.
Mixing up the calling didn't work, mixing up the game play didn't and thus the easiest thing was this roster change.
TLDR Olof, JW and Pronax not being on form, change is good to freshen things up!