Yea maybe. Nothing wrong with that scenario at all. Not sure how DBB is to blame for anything myself but it is what it is. Why don't you think Cahill would make a good DoF though?
I think the general feeling is that she doesn't bring an awful lot to the table, especially when you compare her position to other clubs. When you think about a lot of other clubs, their CEO's are very much front and centre; Levy at Spurs, Woodward (before he left) at United, Purslow at Villa, Granovskaia at Chelsea etc.
Whatever you may think about some of those individually, it's unarguable that they are the head honchos at their respective clubs and have ultimate authority across nearly every aspect of those operations. DBB appears very much a mid-level manager, it seems that there's several rungs up from her and it's difficult to find much evidence about what she brings to the table commercially and strategically.
Don't get me wrong, it's not her fault. We are absolute sham of an organisation. She probably feels like she has two bosses and is stuck in the middle of a constant tug of war between two of the biggest idiots going. However, much of my frustration with Brands comes from the fact that up until the end, he appeared very content to just sit quietly in this mess and accept his lot for what it is. DBB comes across the same to me, she is part of the furniture and as with Brands if they applied themselves more forcefully they could probably have achieved far more than what they were able to. The silence from her office surrounding all of the uproar going on has been quite deafening.
I think Cahill is just cut from a different cloth. He has an incredibly modern outlook, I suspect he keeps tabs on the mood of the fanbase closely and is aware of some of the major changes that we need to see. Having said all of that, I doubt it happens, and even if it did, if we didn't see other changes it would probably count for little anyway.