I think they made the absolute right choice on Worf refusing to give blood. Actually, in my mind, it's one of the times that Worf actually lives up to his reputation. Worf refusing to do it and Picard refusing to order him says a lot about both characters.
The thing that kind of gets me in this ep is that the Romulan is a total douche to Geordie, yet Geordie is friendly from the get-go. If I was him I would probably still be pissed off about that.
If he does have the authority to give such an order and the order could have such great implications for the safety of the ship, then I think he has an obligation to give the order whether he feels good about it or not.
Well I think if Picard ignored his morality and focused on safety it would be a completely different show. It'd be more like if Worf was the captain: putting up the Shields any time they encounter anything new, continuing the drumhead trials in order to feel safer, exterminate any threat no matter the cost.