Remember, a few years ago, the FAA barred Frank Lorenzo from involvement in the airline industry. I can't remember what the precise circumstances were, but I believe a contributory factor was that he was - much like O'Leary - a bully with little regard for the disciplines of running an airline. Having someone like that running an airline or involved in the operational side in any way, could have a detrimental effect on safety.
Perhaps a future Irish Air Navigation Act could include a provision permitting the minister to exclude a certain individual from holding an executive or director position with an airline? Of course, I doubt this will happen; I can't see the Irish DoT having the b***s to stand up to O'Leary. They can either fire shots across his bows now - or wait for some unholy catastrophe which is traced back, to any extent, to his management style and the willingness (or lack of it) on the Irish govt's part to provide adequate oversight.