I'm sorry Aedan, but I don't believe Steelix has a niche in OU. First off, let's examine the niche you claim Steelix fills. Many established OU Pokemon can "more or less" guarantee SR, phaze, and wreak havoc on unprepared teams. The best Pokemon that can do this and thrive in OU are Skarmory, Heatran, and Hippowdon, who each have other niches that distinguish one from the others. Skarmory has Sturdy, an immunity to Ground-type moves, the ability to lay Spikes as well as SR, and access to reliable recovery in the form of Roost. Heatran has Flash Fire and powerful attacking stats to boot. Hippowdon can act as a disrupter of weather-based teams thanks to Sand Stream, and in addition, it also boasts reliable recovery. What does Steelix have that differentiates itself from the aforementioned Pokemon aside from its horrendous Speed stat and lack of reliable recovery? Boasting the ability to OHKO Gengar and Aerodactyl, two Pokemon renowned for their fragility, with a STAB Gyro Ball from a slow Pokemon is no big accomplishment, as is OHKOing Heatran with a STAB Earthquake. As for the Roar / Dragon Tail shenanigans, plenty of other Pokemon can do that. This argument did not factor in Steelix's crippling vulnerability to the top sweepers and lack of reliable recovery. Sorry, but Steelix is simply not viable in OU. Maybe another time.