I personally don't get the appeal of dual doors, sure they're probably more efficient at getting passengers on and off, but to say they improve social distancing is a load of rubbish. Getting on and off the bus is probably the least risky parts of travelling on board, it's the sitting for half an hour next to other people that's the issue! (and I wouldn't even say that's an issue tbh)

They also decrease the number of seats, are no doubt more costly initially and to maintain as there are more moving parts, and really only make sense on routes which have a high turnover of passengers at each stop. I really can't think of any GNE routes that would actually benefit from it in a meaningful way.