Good review! A couple of things about Darkness though....
1. Only creatures that can see through magical darkness should be able to see through, into, or out of it. So, in the example you gave, the drow actually wouldn't be able to see out of it unless that drow also happened to be a warlock with the Devil's Sight invocation. On that note, the devs do need to fix it so that Devil's Sight works correctly and actually does let you see through it, per it's description in the 5e Player's Handbook "You can see normally in darkness, both magical and nonmagical, to a distance of 120 feet." Otherwise, it's almost worthless because it gives everyone attacking into and out of it disadvantage. This spell is the bread and butter of several warlock builds because of Devil's Sight.
2. You should be able to cast it on an object you are holding. This is a massive element of the functionality of the spell. "If the point you choose is on an object you are holding or one that isn't being worn or carried, the darkness emanates from the object and moves with it." This in particular really ruins one of the coolest options for warlocks in 5th edition D&D: cast darkness on something that you are holding, and then run around eldritch blasting and stabbing enemies with advantage while they all have disadvantage attacking you. (This only works if they fix Devil's Sight also)
This spell is currently my biggest issue with the game. The only reason I bothered creating an account for the forums was to bring this to their attention so they can correct it. They way this spell is currently implemented is a major buzzkill for my favorite class.
