I can't see the SK theory, at all. SK has a far grander tool if that was in his head... fire Fisher. I don't see SK meddling in the least with who takes the field... I can see him having a sit down and asking, "What's Up?".... but that's it.
Fisher is more difficult to figure out, for me that is. My guess is that he still believes CK is the 'best' chance but has resigned himself to the fact that it's not working. One might say it's simply that 'spark' he's looking for.. rolling the dice so to speak. I don't think he succumbed to pressure... I tend to think the 'pressure' is why it took this long.
Reminder before going on: I'm not saying I "know" any of this so I'm not speculating with a great deal of confidence.
I don't expect any real offensive strategy change at all. Perhaps, in fact I believe, more conservative but keep in mind... I don't think Fisher was conservative, as far as the 'plays' themselves, to begin with... I think he was conservative in the use of the plays, the timing of them considering field situation, and time on the clock situation, which made him predictable. IOW, very few plays, from a very large playbook, in any given situation.
I do think Goff, under pressure, has a chance to 'appear' more adept at surprise and hitting the big play making it seem a different offensive strategy but not because the game will be called that way but rather - because of one of the reasons he wasn't given an earlier start... an inability to conform to very specific offensive instructions. IOW... he'll be far more likely to play 'off the cuff'.... which personally I think is a good thing. Or maybe 'worth a try'. I do think, from what I've seen, Goff does have more big play ability than CK.