Niall,
I think tough courses can make excellent matchplay courses but they need to offer 'playable' disaster. A good example from yesterday was Rory's recovery on 13? from the steep sideslope to the green. Very tough but playable where as water means instant unplayable and drop (yawn, yawn). I think that is why the TOC makes such a great matchplay course as it is very easily playable yet has the potential for some incredibly tough pin positions.