1. I agree with the dots/surfaces for cantrips. It's a bit OP, especially at lower levels. It possibly gets a little more balanced at high levels, but it's hard to say.
2. There has been a lot of fire on the ground so far lol. However, this does give spells like "Create Water" more usefulness and utility.
3. Agreed. If there is going to be dot damage for stepping in fire there should be a saving throw to avoid the damage. The "Create Bonfire" spell in 5e is a good example. It creates flame beneath the target's feet, but they only take damage if they fail their DEX save despite the spell being a perpetual flame.
