ewarn 'When updating sip, you usually need to recompile packages that' ewarn 'depend on sip, such as PyQt4 and qscintilla-python. If you have' ewarn 'app-portage/gentoolkit installed you can find these packages with' ewarn '`equery d sip` and `equery d PyQt4`.' These should be changed to elog IMO. Otherwise it's too easy to miss, see bug #307513.
Or users should learn how to configure portage's elog functionality... The current defaults are: PORTAGE_ELOG_CLASSES="log warn error" PORTAGE_ELOG_SYSTEM="save_summary echo" thus warning messages (from ewarn) are echoed just like messages from elog. I don't see how switching to elog would improve the situation.
Ewarn has a _higher_ priority than elog, so the message should be more visible in the current situation. If it's not, then that is a question of user configuration, and nothing we can do something about on our end.