Now that we're on the mage side of things, what would and Altmer like Ocato who is deep in Imperial affairs think of the Telvanni? Are they even worth all that much political consideration outside Morrowind?
Ask yourself how a Telvanni Master would rate vs a Mages Guild Archmage ...
Before that huge mess expelling the Necromancers from the Mages Guild almost all the senior members were Necromancers and the Telvanni practice whatever kind of magic they want.
One notable Telvanni - Master Fyr (he is only 4,000yrs old) is frequently consulted by the Elder council, etc. You may remember vivsiting his coprusarium in Morrowind?
It is possible that the Telvanni are generally more advanced in their top ranks than either the Altmer or Bretons, despite the natural talents that those races enjoy. but the Telvanni do not generally 'go to war' as a House. Maybe because no one wants to attack or provoke the older ones - I wonder why?