What you need to be aware of would NOT be the dependencies (what your ports depends upon), but users and any ports depending upon your ports.
If any breaking (backward incompatible) changes are made in resulting pkg,
- you need to notify maintainers of ports that depends upon yours via summaries of PR and/or review if anything needed to be done on their side,
- if your ports are somehow "fundamental" thing like devel/glib20 and lang/python* and having backward incompatible changes, you need to request exp-run (full test rebuilds of the whole bunch of ports tree with your patch) via PR (bugzilla),
- you need to write UPDATING entry if usual upgrading procedure (via pkg, portupgrade, portmaster, ... or historical
make && make deinstall reinstall) alone is insufficient.
In the first case, HEADSUP mail to freebsd-ports ML would be worth posting. It could lower risks to be overlooked for PRs/reviews.
Putting good or not aside, my examples of
HEADSUP,
UPDATING and
the whole commit.