There are better solutions to all of those use cases. Logging? ELK. Cache? Redis. Not sure what you mean by "heterogenous analytics" but that's usually a layer

There are better solutions to all of those use cases. Logging? ELK. Cache? Redis. Not sure what you mean by "heterogenous analytics" but that's usually a layer on top of whatever data store you choose, and we've established that MongoDB just isn't a good data store.