Current Elastic problems:

• slow recording with a large amount of history;
• for small installations it is not advisable to use elastic in view of the architecture of the Elastic itself - complex setup;
• no trends - which increases the requirements for the amount of data that needs to be stored;
• frontend code complexity due to the Elastic support;

Zabbix supports real time data export, which can be imported into the same Elastic, which will make it possible to use the advantages of both systems - operational monitoring and historical data for analytics using Elastic.

Suggestion: drop support in 6.0 or make it work as scalable storage option with fast history syncing.