When looking at the "Visitors in Real Time" widget, every refresh issues two seperate http requests, one for the 24h/30min chart at the top of the widget and one for the content table. Grouping those two into one request would save a lot of hits & transfer time.
When adding the "Real time visitor count" widget to my dashoard, I realized this will issue a request of its own as well, so I assume someone adding all available live widgets to a dashboard would cause quite a rage of requests just by looking at PIWIK. Webhosts offering cheap shared hosting will not be fond of that I'm affraid.
Since the "Real time visitor count" is a quite related metric to the one displayed in the classic "Visitors in Real Time", maybe it would be a simple solution to merge the two and to refresh them by one single http request.
related issue: #6545
Merging the two requests is a good idea! we could issue a bulk API request with both requests.