REST interfaces should help the caller find what they want to do and how to do it.
You would be better served to make the services small and specific and then really analyze the data in the services for caching and use the caching mechanism of the browser to limit data request to only those things that change frequently. This will give you the best of both worlds. Specific data points with less frequent requests.
With large aggregated data calls it is hard to cache because of the disparate uses of the data they contain.
As well, If you back end is done correctly and you build your services with no run-time interdependency, it is easy to scale you application for more request. Scaling at the infrastructure level is always easier than custom code written to avoid resource utilization.