They really don't resemble Phyrexians much at all other than being mechanical. Phyrexians are nightmarish fusions of metal and flesh which worship brutal efficiency as the ultimate form of perfection and want to convert all other life into themselves in painful and horrific ways. Warforged kinda fall short of that bar.
the guy who wrote Eberron chose his own methods of screwing with people. i specified Artifacts Cycle because we only meet 6 phyrexians in the Brothers war. the 4 dragons, Myshra, and Geth. The WF are built in similar manner to them, minus the bodyhorror, keeping the souljar