I thought we would've beaten Hull in the final but it's impossible to say for sure. But you're right, he did an amazing job getting us to that position in the first place.
I also laugh at some people (not Saints fans) saying "is he only a good manager because of the spying". Well we beat Fulham, Arsenal and nearly Man City without any of that. Plus the other teams who have secured training grounds. Does make it even more silly that it needed to be done in the first place.
He's obviously been a part of this spying throughout his career, but it's only been a problem this season because of the rule.