«جاءني زيد العالم» and «جاءني زيد الجاهل» are both adjectival constructions. Their grammatical status alone does not fix their purpose. In one audience an adjective identifies which person is meant; in another it expressly praises or reproaches an already identified person.
ContextLikely rhetorical purpose
Two namesakes are knownIdentification
Known person; admirable quality foregroundedPraise
Known person; defect foregroundedBlame
Hence no rhetorical intention follows from the adjective alone. The speaker's aim and hearer's prior knowledge must also be considered.