1) Except the other children will have magic, while these would not. Make whatever scenario you want to, that won't end well.
2) Except the number of abominations isn't high, and the Circle worked just about everywhere else. The only times when it didn't, a fanatic started trying to overthrow templar authority, with most of the innocent and content mages caught in the crossfire.
3) Comparing a warrior to a mage is foolish within itself, but generally in magical societies those with the most power rule the longest. Duels happen in the streets in Tevinter. Your mage utopia would be no different.
4) They could do all of those things in the Circle, families aside which should be reformed, so I'm not seeing your point. Templars didn't rule their lives, they ruled their lives. Templars observed and made sure that the mages didn't threaten the rest of Thedas, and then protected them from those on the outside who wanted to kill them. You really have no point here.
1)It might end in bullying or harassment, but how would it be any different to most education? And as I said, separate schools for mage children and non-mage children. Kids don't show magical properties till 6-12 so the first couple years of their lives would be intertwined and when the powers started to appear, they would already have friendships/bonds. The division often wouldnt be that great.
2) we are giving 2 examples in the DA universe. Fereldan which did seem to be a well functioning tower yet still had a huge number of students join Uldred in his attempt to take over the tower. The other one we see is Kirkwall, as I posted earlier, every single mage you encounter not you or Bethany is a necromancer, bloodmage or abomination. There are almost no exceptions.
3) in societies with Mages and civilians sure, mages will rise given their power and ability to manipulate. All mage societies could have order but you are right, they would probably devolve into the strongest rules. So? at this point they are ruling over other mages. Once again a small percent of the population.
4) Baring the top tier of mages (those in the College of Magi, who were allowed to leave to meet at the council meetings in Cumberland) you are not allowed to leave the tower/tower grounds. You are discouraged from relationships, but its not strictly enforced. If you do have children they are taken away from you regardless of if they are mages or not. If you allow mages to have kids in the tower, doesn't that counter your first point of how terrible it would be to be normal in an area dominated by mages?
My solution is about giving the mages a degree of freedom, the choice to have families, friends, build a house and live in it, own land and be something other than a mage. They can do this in isolation without threatening the millions of innocent folk who don't want to have anything to do with mages, and when one does go bad as they always will, it will be their issue to solve and their lives on the line. They will also be more capable of dealing with it being naturally powerful.