McCarthy had a really good game at the Hawthorns in the first leg of the semi-final, as I remember it, which involved a lot of claiming contested crosses. As we all know, Bazunu would've flapped being put under those kind of deliveries
There was also a cracking reaction save at Wembley to stop Leeds equalising. So I'm not sure I particularly agree with your assessment of McCarthy's contribution to our playoff success
(I'm not a McCarthy fan and feared the worst for the playoffs with him stepping in... but to rewrite history and suggest he didn't make a significant contribution to our promotion in those games is unfair)