Oblivion's Conjuration is genuinely designed differently, yeah. The summons are dumber AI-wise - they path poorly, get stuck on geometry, and don't respond to combat as fluidly as Skyrim's. That's not just you being used to newer pacing.
The bigger issue though is that Oblivion's spell variety feels thin because it is thin compared to what Skyrim ended up with, especially post-Dragonborn DLC. Oblivion has the basic Dremora Lords, Daedric servants, and a few Atronach flavors, but Skyrim added Spectral Assassins, Storm Atronachs, Dremora Warlords - more tiers and options. Oblivion's school also suffers from being balanced around how broken Conjuration could get in the late game (summoning two Dremora Lords and watching them solo dungeons), so the early spells feel underpowered to compensate.
As for why nobody talks about it - Destruction and Restoration are flashier and more immediately satisfying. Conjuration requires you to babysit your summons and watch them fumble around while you wait. It's not fun in Oblivion the way it became in Skyrim. If you want to make it work, honestly just lean into Dremora Lords as soon you can afford them and accept that your summons are more of a distraction than a partner. Or respec into Destruction - it's way more viable in Oblivion than people remember.
