correct me if i'm wrong, but did Keane not set up Stephen Ireland's goal against Wales with a lovely through ball? He also left a dummy run through to Ireland for his goal against Slovakia.
He's a good player playing in an average team. Week in, week out he plays in a better team and consequently scores more goals. His conversion rate of chances is not great, but that's just the way it is, and the team will just have to deal with it.
He has proven over the last few years that he is Ireland's best striker, so the question for those calling for his head is to identify a better partner ship than Keane and someone else.
I do agree though that he shouldn't be immune from substitutions.