The following changes have already occured in OpenBSD 5.6-current and will be part of the May 1st OpenBSD 5.7 release:
nginx has been deprecated and removed from base, to be replaced with the new httpd (spawned off relayd)
A new rcctl(8) utility to manage rc.conf.local content (mainly to aid automated configuration such as puppet, ansible, salt, cfengine etc)
Long disabled crypto(4) device gone for good
sysmerge(8) to extend itself to handle package upgrades
... plus lots of hardware support improvements, bug fixes.