Steinberg shared on their forum information on the roadmap for versions 1.7 and 1.8 (Last release was 1.6 and on average new versions are released each month plus to 10 days).
1.7 – Inter-app Audio support
1.8 – Automation
So finally we will see Automation. With it’s pretty easy-to-use midi editor and greatly optimized GUI it should be best host for IAA apps (as long as Apple is not releasing their own IAA host version – Logic or updated Garage Band).