Were there any magic restrictions, or skill restrictions, for factions or ranks in factions in Oblivion? I know there was such a restriction to all factions and ranks in Morrowind (the best game in the modern aeries, imo.).
Nope, none. Though I do recall it being perhaps a mite harder to wing your way through than it is in Skyrim. Certainly for the Mage Guild anyway. I think one quest you had to use several different spells/types of magic to progress and that stopped me in my tracks for a little while.