One of the creators of Django once told me, "Flask is what Django would have been if we designed it in 2010 instead of 2006." Sometimes smaller is actually better.
There's a difference between software having features and having opinions. For example, Pylons (http://www.pylonsproject.org/) ships with a large feature set but doesn't feel like you're forced to use any of them, whereas Django ships with a larger feature set and doesn't give you much choice.
Naturally, there are advantages and disadvantages to both approaches.
