A title has a marketing value and can make or break a movie, sadly.
The Shawshank Redemption was a flop at the cinema, made a fortune on DVD and secondary markets and is pretty much touted as one of the best movies of all time.
Liquid Sky was a crap film I saw in my teens and still hate. But "Eternal Sunshine of a Spotless Mind" is one of my favourite films.
I have to disagree that a titles length is indicative of a films quality, but I do think that may be indicative in same genres.
A crap title can make it hard to find your audience. Think of it as marketing, it has to get a clear message to the people you are aim to reach, your identified audience. If you do that, a producer that also knows who that audience will recognise a good marketing focused title.