Powers
Your mana pool is divided into 3 "bars" (Unfortunately not visualized because I have no experience with D1 texture modding nor am I good enough of an artist. If anybody creates alternate mana bar graphics to suit this mod I will include it). After a period of time, if it is not full, the mana pool begins to slowly regenerate until it is. The speed at which mana regenerates has been slowed down significantly, though the waiting period for it to start has been untouched. A bonecharm can grant you one additional bar (4 bars total). To allow casting powers in the heat of battle, remedies immediately restore 2 bars of mana.

Falling Star (mana from drop assassinations) restores 1 bar of mana
Plague Affinity (mana from weeper damage) restores mana to full after receiving any weeper damage
Spirited I and II (more mana from remedies) makes remedies restore 2.5 bars at level I and 3 bars at level II
Spirit Water (mana from using water faucets) restores 1 bar of mana

The effects of Whirlwind (faster sword swings) have been doubled
Welcoming Host (longer white rat possession) adds an additional 30 seconds of possession instead of 10
The effects of Water of Life (health from using water faucets) have been quadrupled, now giving you half as much health as a potion per sip
Doubled health received from Tough Skin (higher max health)
1.5x speed increase for Swift Shadow (faster when crouched), Undertaker (faster when carrying bodies) and Acrobat (faster climbing)
Reinforced Bolts make crossbow bolts indestructible
Rat Scent reduces the range of rat swarm provocation further
Albinos makes all rats white
Twist of Fortune (chance for remedies to give full mana) has had its chances doubled

Notes
This mod does not work for Knife of Dunwall or Brigmore Witches. It does not touch the Void Walker bonecharms. It requires you to have installed Full Regen. This mod includes a configuration file for it. If you wish to edit it to your liking, keep in mind the following:

• Maximum mana must be 60 to avoid breaking things
• Regen amount's minimal positive value is 1. Fractions are not allowed and are rounded down. So if you set it to, say, 0.5, it will be 0 and mana regen will not occur at all
• Step time makes mana regen slower the higher it is and vice versa
  

This mod overrides a few localization files. It already includes a few changes from Text Corrections. If you are using Text Corrections or any other text mod, make sure to install this one after, not before your text mod of choice.
Credits
¿ʇɐɹ of dishonored discord for feedback
marlboro man of dishonored discord for giving the idea to make this
soup of dishonored discord for thrilling and hyper-constructive feedback. Their input has proven to be invaluable