If you have a lot of different things being cooked, you want the brigade system with individuals' prep, holding, and cooking areas distinct and the flow across their space minimized. That includes little things like having squeeze bottles of water at their station so they don't have to access a sink to add liquid to something and all the dishes they need to plate what they're working on. If you have labor intensive assembly of a few things, you want assembly line, and then it's more important to have lots of contiguous, double deep counter space so you can stage materials for each step and slide things along. For a brigade system, you usually have an aisle wide enough for someone to carry a hot pan past you while you're working without having to worry about bumping into you if you don't suddenly lurch backwards. Oh, and somewhere to step out of the zone where you have to be on alert for things like that. I've seen that both with one sided prep areas with eight feet or so to the other wall so you can physically back out of the line, or a four foot aisle and walking down the line to the storage freezers (which people aren't going into constantly once everything is prepped) to step away.
In either case, finished materials need to be staged to be removed from the kitchen, and a parallel path needs to bring dishes back without getting in path of the cooks.
But back to the primary topic, most of the kitchens I've seen in houses simply are not functional. When we were house hunting a few years ago I would say half the kitchens were laid out where, due to other constraints of the house, they could not be remodeled into something that wasn't a pain to work in. It's fine to have to cook in some place that's a pain once in a while, but in your own home? Yeesh.
