In October 2015 Google announced the availability of calculated metrics. Although it is a really powerful feature, there are some drawbacks as well, especially when you need to define more than 5 metrics per view or you need to work with other than numeric-type data.
Dataddo contains a great feature called Structures that besides merging the data from multiple sources together allows you to define almost unlimited number of calculated metrics based on the any data available within the structure. Therefore using Dataddo your calculated metrics definition is not just limited to Google Analytics, but also available for Facebook Insights as well as for Twitter analytics (or any other data ingested to Dataddo).
Please find more information about Dataddo Web & Social data analytics platform.