McCullough is old school, he could be transferred back to the 80's; makes his tackles a lot of tackles, passes to the right player and sometimes kicks.
The perception of the role has changed and people want a dynamic runner, who takes off and makes ground like Granville.
I think it is whatever suits your team. Parcell and Granville are one style and McCullough is just as effective for his side. I used to think that Granville had to curb his running and his first instinct was always to run and pass second; he's changed that this year and he is a much more well rounded hooker. Teams would talk about getting to him quickly and making him take that second option because he would do it in a pressured hurried way.
Parcell is smart, quick and probably somewhere between the two, nice pass, nice run and fast while missing next to no tackles.
You can't carry four players in one position who could all play NRL. Granville was always going to follow Green and take his shot, which is what Parcell is doing now too. Parcell is 22 and done his time in the ISC, if he hung around again on the second tier cap and playing for the Jets; he might not get another shot at a top 25 gig.
McCullough and Nikorima will be the Broncos' options now and it's not a bad position to be in. Regardless of what the other two do over the next five years.