im not really discounting bent laterals, it was just an example. i think we can all agree that some of the iso-movements that a lot of bb'ers use are overkill.
i used to use a lot of iso movements after my core movements like you suggested. since i dropped them, my physique and strength gains have been far better.
i know a lot of guys like to use a "finisher" for that great burn feeling. my theory is that if you just busted out 5x5 with some heavy bent rows and weighted pull-ups, your rear delts are already fried. and it is possible that subsequent iso sets may lead to over-training, while not really producing a whole lot in gains.
maybe thats just me. although i consider myself to be a bodybuilder. i pride myself on training hard and heavy. i live to train heavy, i get a natural high from it. i just dont get that same feeling from a set of concentration curls.
i am also of the opinion that you must first build a sold foundation of muscle before concerning yourself with your rear delts or serratus anterior etc... therefore in my opinion those exercises would only be beneficial once you have attained the size that you are after, then you can worry about "fine tuning" the physique.
wow, that was way to long and im sure some people will have to disagree with me. flame away.