I have to agree with the majority opinion that hydraulics are not needed on such a light helicopter. The stick forces are so light anyway, so what would the hydraulics be doing.
I dissagree with WB who suggests that hovering would be made easier.
What the Robbo needs is a fuel injection system to reduce the carb icing problem. But this is a UK problem and highly unlikely to get into the R & D cell.
A super little helicopter spoilt by the 'Barb of the Carb'
Hydraulics are normally fitted to reduce pilot input loads at the controls. I understand in the case of the R44 they were introduced to banish the feedback forces and cyclic vibrations that are evident on the original model.