I would say that "too heavy" is a relative term. Everyone has different needs and desired looks. Others are entitled to their opinion and what they put on their face, but I don't have to agree with their point of view when it comes to my face.
Personally I think MAC has a great range of products and colours. That been said, I still don't use MAC exclusively. There are so many great products/lines out there that I would never limit myself to just one.
As others have mentioned, I completely agree that application technique, application tools and product choice have so much to do with how it turns out.
Oh yeah......the less MAC "they" buy, the better chance for me to get my hands on an LE.