Long, long ago, I had the pleasure of flying the wonderful Puma (a hecloplater). Won't bore you all with the background, but helos are invariably driven from the RHS. At the time the Puma was usually flown with one pilot and one crewman. Apart from the single sqn QHI, the sqn had a few training captains and some LHS captains. The TCs and LHS caps could all captain the ac from the LHS. They were all experienced operators and had completed the LHS handling sortie. The latter was an attempt to teach you how/when to take control of the ac if the ac was mis-handled from the RHS.
Being a Helo an enormous amount of our flying was spent very close to the ground/buildings/underslung-loads etc. This, although not excessively risky, didn't give the LHS pilot much time to recognise any error and, if needed, take control. The beauty of this system was that it allowed many inexperienced sqn pilots to do most of the hands-on flying while being monitored from the LHS. Therefore, the sqn JPs rapidly benefited by doing the majority of the flying.
The Puma had no nosewheel steering, but did feel somewhat different when flown from the other seat. At no stage were there any limitations impossed on the JP flying the ac from the LHS.
I accept the point made above that, what works in one fleet may be totally inappropriate to another, but do think we make too much of an issue over what a co-pilot can or cannot do. They are invariably competent aviators that lack experience. The more they operate/handle the ac the better.