In an environment where we have a lot of dashboards it's being detected that all web API requests use a lot of SLNet processing, is this something that the new dashboards app can handle better?
It's not easy to give a straight forward answer to this, but i'm inclined to say that performance will be better. Do note that this highly depends on the content that is shown on the dashboard.
A big evolution for our newest web application is the use of web sockets (eventing). This is a push-based mechanism which enables the client to be notified of a change rather than polling the data at a certain interval. Polling requires the data to be recalculated every time which did put a lot of load on SLNet.
Even when web sockets are not enabled, the framework our applications use has been improved to do polling on changes, rather than polling individual web API methods.
Note that you can enable web sockets and set the interval in the settings of the dashboard: