I think the hit chances are fine. In our d&d group, vision is a factor. If you have no darkvision and there isn't a reasonable light source nearby, attacks are made at disadvantage. This is to help with immersion. I actually love how darkvision plays a role, and I hope they add a day/night cycle so that it plays more of a role. Statistically, humans are the best in game for EA, because they are the only race to start with 3 ability scores with a +3 modifier. But if darkvision became more impactful, that may not be the case since they would be at a disadvantage more often without aid.
Why would they make a cantrip, a level 0 spell that can be spammed all day, do comparable damage to a 2nd level spell? That makes no sense whatsoever.
I think the combat encounters are actually very well balanced, but slightly on the "to easy side" (assuming you are in a level appreciate area). If you use some buffing spells/abilities or conditions you will have an easier time. If every party member does nothing but attack, you are at a disadvantage. Shadow heart can bless your party to hit easier, warlock can hex enemies to make them more vulnerable to condition effects, etc. Utility spells and abilities are there for a reason.
Unfortunately, the 5e edition makes the early game much more difficult than later game for hitting. Starting out you won't have very good proficiency bonus or weapons and any armor will give you a 50-65% chance to hit before other modifiers. Later in the game, since AC has a soft cap of 20, as you get better gear and more xp, hitting becomes much easier.
