with runtime and/or dataindex if we can have embedded TC/MC/JC it will be a good addition to the platform and faster prototyping.
Not sure what will be the right place for the above Data Index or Runtime. 

But integrated TC/MC/JC will definitely be some thing any future users of Kogito will be benefitted. 

WebJars can be published and only the route information of the 3 can be configured.
Regarding security underlying quarkus/springboot will manage. 

The way we have health addon in quarkus and acutator in springboot.

This will reduce the option to run separate pods for TC/MC/JC and keycloak.