Ian was a writer that is a member of what is called the "SEGA of America lore team", which is basically a lot of people who work at Sonic and they would discuss lore and other stuff about developing Sonic's world, but even in that Chris was "his boss" hierarchy-wise.
People often talked more about Ian because he has a podcast where for the last decade, he used to answer Sonic questions, but he doesn't do that anymore. But since he still is a writer that goes around a lot not just in comics, but also the games and animated shorts, people still talk about him a lot (Especially since he writes a lot, it's easy to pick his tropes, so haters will just talk about that non-stop).
But since the start of the year, there was some moving in the roles, Evan Stanley became the Lead artist for SEGA of America's Sonic Lore Team and Chris became the Lore Manager, so who knows if Ian has a more definitive role at Sega, or he is just a happy freelancer that constantly gets to work on the same franchise.