For many, the choice of their favorite city is inextricably linked to their favorite hero. So, in my opinion, it would be wrong to do that.
But when, for example, a Necromancer faces another Necromancer, that's a real problem. For now, it's difficult for me to say what would be a fair trade for the hero (it might even make sense to agree on starting with Tant-Ghal).
And Tanta should have been banned from selection a long time ago.
From a balance perspective, starting with random heroes looks interesting (although not without some randomness). And as Reddy said, this is a tournament of favorite castles, not heroes.