Arguably yes. Of course there are many factors, and you can't use only one. It's miserable to pretend the thread is about using length as the only factor. So if a movie is good, then more of it will be better. Assuming it's not artificially prolonged (by adding useless side plots for example) and quality doesn't suffer because of it. You can flesh out characters better, add more depth to the whole plot, some cool action etc.. And if it gets too long then you can turn it into great series.