It's hard to equate basketball to corporate life, but I think the attitude of promoting from within at a program like Illinois does more harm than it does good all things considered. In a coporate enviroment, you often have a number of positions in the same line. For example, there will be a number of accounting supervisor positions. Sure, you need some fresh perspectives that outside opinions can bring. But internal promotions foster engagement and a feeling that you can work up the ladder. If I'm hiring, I'd prefer an internal promotion and would use that as a tiebreaker if I had two candidates that were equal in other ways. However, I'll always select the most qualified candidate. I don't care about internal politics, friend connections, etc. I want the best skills, accomplishments, and qualifications when I'm hiring. Call me unsentimental, but internal politics really don't sway my thinking a lot.
A Big Ten basketball staff only has five assistant coaching positions, and we all know how transient the profession is. Maybe you have one for an internal promotion role, but the other four really need to be for experienced assistants. A Big Ten staff isn't where you have "on the job" training. It's where you hire people who have proven themselves at other positions and are looking to eventually be head coaches one day. On a given top Big Ten staff, you should have at least three - and probably four - coaches who should be getting calls and interviews for promotions (head coach at a smaller school, lead assistant at a big school) as their next step up the ladder. Now maybe they have done that and are good staying as an assistant (i.e. Antigua), but if 75-80% of your staff isn't fielding some sort of interest from other programs for promotions then you're probably doing it wrong.
On the current Illinois staff, who is likely fielding calls and interest for promotions? I think we can all agree that Hamer isn't. Let's assume that it's only Antigua and Alexander (again, only an assumption on my part). If that's the case, that's 40% of the assistant coaching staff. That's not good enough for a program like Illinois, in my opinion.