Hi MariaP,
Thanks for your idea. It can indeed be helpful and we have implemented it for new web apps. As you might know, we have recently released reactive web apps, that take the best of what mobile apps have to offer, and builds upon that with several improvements.
One of the things that is similar in these new web apps is that you can fetch data from other sources, that, as you were saying, makes it possible to refresh individually.
You might also like to know that Aggregates and Data actions have also have a new property "Fetch", that allows you to specify that they only run on demand, i.e. they do not run automatically when the page is shown (check it out on the link above).
Thanks again for your ideas and keep them coming.
Cheers,
Tiago Simões