Target: Living creatures in a 20 foot radius within 100 feet
Effect: The target makes a Charisma saving throw. On a failure, it falls unconscious for 1 minute or until it takes damage or someone uses an action to shake or slap the sleeper awake. If its current hit points are greater than 4 * your highest caster level, it can make a Charisma saving throw as an action to end this spell’s effects. Non-deafened targets can make a Charisma saving throw to end this spell's effects as a reaction in response to loud noises, like shouting.
Why: Vastly simplifies the spell. Keeps the spell relevant against creatures with higher hit points by allowing them a recurring saving throw to end its effects. Applies the effects only to living creatures for reasons of versimilitude (though I wouldn't be adverse to it affecting non-living creatures).
Target: One creature within 100 feet
Effect: The target takes 1d4 + 2 + ability modifier force damage.
Why: Improves the spell to be on par with other damage dealing cantrips.
Target: A creature within your reach
Effect: Make a magical attack against the target. If you hit, it is restrained for 1 minute. If its current hit points are less than 8 * your highest caster level, it is instead paralyzed for 1 minute. As an action, a creature affected by this spell can make a Constitution saving throw to end this spell’s effects. Undead you hit with this attack gain an extra move on each of their turns for 1 minute instead (you don't need to make an attack roll against willing targets). If you choose, the target exudes a carrion stench in a 10-foot-radius cloud while this spell's effects last. Living creatures other than you in the cloud have disadvantage on checks.
On a miss, your hand retains this spell’s magic, and you can attempt additional attacks with your ghoul touch on later turns, until you make a successful attack or until 1 minute passes.
Why: Buffs Ghoul Touch to be roughly on par with other level 2 spells. Allows it to work at full effectiveness versus powerful albeit weakened opponents as it requires the target be below a current HP threshold rather than a max one. Grants it additional utility/dual use by buffing undead (synergy with the Necromancy specialty).
Target: Each creature in a 15-foot cone originating from you
Effect: The target makes a Constitution saving throw. If it fails, it takes 2d6 thunder damage, is pushed 15 feet away from you, knocked prone, and is deafened for 1 minute. If it succeeds, it takes half as much damage and is not pushed, knocked prone, or deafened.
Why: A concussive wave of sound and force seems much more likely to be resisted by Constitution than Dexterity. Improves Thunder Wave's versimilitude and puts it more on par with control spells of its level.
Target: Each creature in a 15-foot cone originating from you
Effect: The target makes a Dexterity saving throw. If it fails, it takes 4d4 fire damage and takes 1d4 fire damage at the start of each of its turns for 1 minute. A creature can end this recurring damage by using its action to make a Dexterity saving throw to extinguish the flames. If it succeeds on the initial saving throw, it takes half as much damage and doesn't take the recurring damage.
The spell ignites unattended flammable objects in the area
Why: Improves Burning Hand's versimilitude and puts it more on par with control spells of its level.
Target: Any number of creatures in a 20 foot radius originating from you
Effect: The target must succeed on a Charisma saving throw or be frightened for 1 minute. While a creature is frightened by this spell, it must use the move on its turn to move away from you. If an affected creature takes damage, it is no longer frightened. As an action, a creature affected by this spell can make a Charisma saving throw to end the spell’s effect on itself.
Why: This is an overpowered encounter breaker. Granting it a Ghoul Touch method of allowing a creature to break the effect at a cost helps balance it. Changed the saving throw from Wisdom to Charisma, as it makes more sense (the latter being force of will and self).
Ray of Enfeeblement
Target: One creature within 50 feet of you
Effect: Make a magical attack against the target. On a hit, it takes 4d6 necrotic damage, it has disadvantage on strength ability and skill checks, and deals minimum damage on strength attack rolls. As an action, it can make a Constitution saving throw to end this spell’s effects.
Why: Allowing the secondary effect to apply to all targets while granting targets the opportunity to make subsequent saves at a cost helps balance it, while permitting its applicability to higher hp targets.
Requirement: You can cast this spell only as a reaction in response to a creature casting a spell within 50 feet of you.
Target: The cast spell.
Effect: If the target is a 1st-level spell, it is negated and has no effect. If it is a 2nd, 3rd or 4th level spell, you engage in a magic ability contest with the caster, otherwise this spell fails and is not expended. If the target is 2nd level you have advantage on this check. If it is 4th level you have disadvantage on this check. If you win this contest, the target is negated. If you fail, this spell is not expended. If you negate the target, you cannot take an action on your next turn.
Why: Makes Counterspelling worthwhile, by making costs proportionate to effects. Losing an action and a spell use on a failure is overtly harsh and makes this spell nearly pointless. Why would you sacrifice a spell slot/use, an action, and a reaction for a _chance_ of negating a same or slightly higher level spell?
Target: One creature within your reach.
Effect: Make a magical melee attack against the target. On a hit, it takes 2d6 + ability modifier necrotic damage and you regain half as many hit points. Undead you hit with this attack regain hit points equal to the damage you would have dealt (you don't need to make an attack roll against willing targets). For 1 minute, you may use your action to repeat this attack.
Why: Appropriately classifies Vampiric Touch as a melee attack. Brings Vampiric Touch up to par with other level 3 spells like Dispel Magic and Stinking Cloud.
Target: Choose a living creature within 50 feet of you that can hear and understand you
Effect: The target makes a Wisdom saving throw. If it fails, the target is charmed until the end of your next turn and you choose an action for it to take next round that does not involve knowingly attacking or harming itself or its allies, and decide how it will move on its next turn. If the creature’s current hit points are 10 * your caster level or less, it is instead charmed for 1 minute and you choose an action for it to take and how it will move on its next turn.
Why: Current HP threshold rather than max HP threshold + a secondary effect for creatures above the threshold makes the power more consistently applicable.