Add a 'lint' check, to provide warnings for common misconfigurations
Host nodes without any addresses attached
Add a CLI for generating a basic setup and then adding nodes/monitors/observers to it.
Potential federation / referral for sibling managers
Add optional authentication support (ZAUTH)
Allow 'address' host DSL to accept multiple addresses in one call
Allow disabling an ACKed node (kschies)
Action dependencies -- as an example, if an action sends an email, don't trigger if the email service is offline. Potential action "chains", ie: If the email service is down, use a separate out-of-band action that sends SMS.
Flapping state detection
Add a one-shot runner command for development of monitors. Loads and runs a monitor one time, maybe with some output describing how often it'd run, what its skew is, etc. [will@laika]
Add some default monitor types and utilities
ftp
imap
pop
smtp