The package dependency speedup was committed by portmgr, unfortunately it was not the latest version of it. The most recent version is scheduled for an experimental ports build run (my patch also contains the possibility to switch of the registration of implicit dependencies, if enabled it gives a much better picture regarding which port needs to be rebuild (portrevision bump) in case a dependency changes).
Patches for speeding up “make clean” are also scheduled for an experimental ports build run. The pkg_create patch was also committed to ‑current.
With all those stuff an update is much faster now, at least for those ports where the compile/build time was much lower than the infrastructure processing (I doubt you will see a significant change in a build of OO 😉 ).