A while back I stumbled upon a great post by Jean-Baptiste Queru. It describes the incredible depth of the modern technology stack. Layers upon layers of complex science, hardware, and software, each layer creating a simpler abstraction around the previous. This ultimately enables our paltry human brains to create amazing things that would otherwise be impossible (or really difficult). This is, in my opinion, the lifeblood of modern software development.
This is not to say that significant value can't be created by a framework with a small codebase. However, given the choice between two frameworks with equally well-written code, I would probably opt for the larger framework1. Choosing a framework for its small size is a premature optimization. Taking this a step further, given a choice between tying together two unrelated "micro-frameworks" and one larger framework, I would definitely opt for the latter.
Tom Dale begins a similar post with the following:
Why does it take big teams, big budgets, and long timelines to deliver web apps that have functionality and UI that approaches that of an iPhone app put together by one or two people?
Although I'm not going to comment on the number of people required in either case, I completely agree with the implicit assertion that mobile development is more efficient. As a developer who has been building desktop, web, and mobile applications for years, I have always felt that, specific to web development, a larger amount of energy goes towards dealing with the frameworks involved, rather than the problem being solved. There is also an uncomfortable, almost nauseating, feeling that my code is not as modular and reusable as I would like and have come to expect from other development stacks.
In any case, as web applications continue to become increasingly complex, the emergence of larger and richer frameworks is inevitable - and it's about time.
1. It is important to clarify this choice with respect to size and horizontal bloat. Here I am using the term larger to denote a framework which has a stronger abstraction/more utility for what I am actually using it for (as opposed to a bunch of unnecessary features).