ELK Kibana Room for Improvement
One area that could be improved is security. Being an open source product, if you want to add security, if you want to add authentication, you've got to use a third party plugin that may or may not cost you, or alternatively upgrade to their subscription service, which is a downside as well. I think the types of visualizations are nice, but I think there's room to add more without having to go to third party plugins to do that. Just comparing the total number of visualizations that it provides compared to Grafana, you can see that it's lacking. The UI experience isn't as rich as it is with Grafana or certain other tools.
I would like to see better authentication options, typical authentication options, like active directory and LDAP as well, just a richer UI with more graph type options.