Thanks to the intrepid detective work of Jørn Reidel and Ahmed Marof, it looks like one of the big hurdles for doing a full migration from using the legacy Google Analytics and Google Tag Manager SDKs to the latest Tag Manager + Firebase SDK is now a non-issue. The issue is, of course, Product-scoped Custom Dimensions or more specifically the lack of support thereof. Until now, I'd been holding against recommending the migration to anyone with Enhanced Ecommerce tracking set up simply because the documentation didn't mention the possibility of sending these custom definitions to Google Analytics.
One of my favorite (and most popular) articles in my blog is Improve Data Collection With Four Custom Dimensions. In that article, I show how you can improve the quality and granularity of your Google Analytics data set with just four Custom Dimensions. The reason I chose the four dimensions (Hit Timestamp, Session ID, Client ID, and User ID) is because I firmly believe that they should be in Google Analytics’ standard set of dimensions, but for some inexplicable reason they aren't.
Last updated 22 May 2019: Added expiration of currently open tabs. In this article, Jethro Nederhof of Snowflake Analytics fame and I will introduce you to some pretty neat web browser APIs. The purpose of these APIs is to find out more about how the user navigated to the current page, and what's going on with their browser tabs. There are so many things you can do with this new information.
Since writing my rant about the schema conspiracy of web analytics platforms, I've been giving the whole idea of hit-level data collection a lot of thought. Sessionization is very heavily implemented in Google Analytics, which is understandable, but the regular Google Analytics API just doesn't give you the kind of information you'd need, if you wanted to stitch hits together differently in your own backend. In fact, there are four distinct levels of aggregation that are not exposed via the API, even though I think they should: