I think it's best if both Roughy and Roberts are able to pinch hit forward and get plenty of practice doing so this year. Both are more than capable defenders, particularly in a zone set up and both can go forward but don't have a lot of exposed form there at the moment (need some more exposure to help identify the KP (type) we should be pursuing later) Roughy is unique in that he can comfortably play ruck, defend or spell in the forward line and provide a contest which is enough in short stints when our smalls are so lethal.
Injury free and all available, Talia, Roberts and Hamling can all fit in the backline in a set up where Roughy is no1 ruck IMO. Roughy can then go back (covering opp ruck resting forward) or go forward while Boyd rucks maintaining height and a contest up forward. If he goes back, Roberts should have the capability of providing the tall option forward whilst Boyd rucks and Roughy defends. I think it's very workable in a zone defence with the players we already have on our list. An injury to any one of them creates a problem though so we need cover. But do we need a KPD, Ruck or KPF. I always favoured KPD this year, but seeing how Roberts and Hamling (and the zone defence generally) performed even without Talia (it held up well), I'm not sure we'll know for a few rounds yet.