Opkg, being based on ipkg, is not a real package management, it's more of a package & package dependency installer. AFAIK it doesn't have *any* support for handling package conflicts, file replacements, alternatives (maybe not even running package specific scripts?).
Not true... - it is an package management system. - but it's also an build system... (AFAIK much more handy than RPM...) - ipkg is .deb compatible - it has support for conflicts, and suggestions...- it runs replacements, alternatives, postinst and prerm scripts (just like .deb)
-- ---