Good move or bad? I think IBM massively overpaid (nearly 1/3 of their own market cap, in a cash deal), and basically made the Red Hat stakeholders an offer they couldn't refuse.
Future of Red Hat? The claim is that Red Hat will continue to operate independently. We'll see how long that lasts.
Future of AIX? IBM could kill AIX off, and make some money selling consulting services to people who need to migrate from AIX to RHEL as a result.
So many questions... some of which hit close to home (and pocketbook) for me personally, since I currently work for another IBM business unit.