i think applying clan strats to pub games are highly effective and very efficient if done right, but disastrous if executed poorly. however, i think that pub strats are almost always disastrous if done in clan games.
key and cwag play very clannish type games, where everyone listens and such (actually, i dont' remember seeing key comm, i'm just assuming), so their strats are much more aggressive and, some might say, risky. it also means you won't usually see them in pubs. most pub comms try to plan for mediocre to poor marines. which leads to defensive commanding, which leads to loss against a booming (standard) alien strat.