I think the mobility factor is a bigger issue than height - may not have emphasised that enough.
Hilditch is definitely old school, which shows as his last 4 years were solely as a prop. A better example would be Ken Stewart from Souths who was also tallish but old school - and replaced by a young Mario Fenech very quickly. Irony is that Parra then bought Stewart to replace Edge - but in his final year he too was converted to a prop as the youthful and more mobile Moseley took over.
Parra were well behind some other Clubs at the time with this hooker 'revolution' - about the only thing they were behind in.
Would have liked to have seen Cunningham ply his trade in the NRL for a year or so. There's a good history of Pommie hookers doing well in Australia - Mike Stephenson, John Gray, Lee Jackson and a small cameo for Brian Noble.