There have been numerous efforts to find a way to
reform charms and other buffs, and for good reason: pre-battle buffing is tolerable when it's a significant fight, but when literally every fight starts with a series of spells, it becomes fairly tedious. As long as one of these spells is castable, regardless of the spellpower, it is strictly optimal to cast it before every non-trivial fight, of which Crawl has loads.
There are two kinds of buffs. One is dominated by the charms school, though some of these spells (notably the Book of Frost buffs) are outside that school; for these, I recommend removal, with replacements or additions as necessary. The other is transmutations, which requires a bit more finesse; I have a few ideas of how this might be accomplished. For ease of reading, I've divided these up into spoiler'd sections.
Charms and Charm-like Buffstl;dr: every buff spell is removed and replaced with an equipment ego or amulet. The Charms school is removed, and dual-school spells are either given a new school (usually Hexes) or is turned into a single-school spell. Skald is removed as a background, and Book of Battle goes away.
- Condensation Shield and Ozo's Armour: Both spells are removed and replaced with the Amulet of Ice, which replaces the Ring of Ice. The amulet gives rC++ and rF-, an Ice enhancer, and gives the player the AC-boosting effect. On taking damage, these defenses fall away over time, and come back following a sufficient number of turns, as with the DS mutation. The effects of the amulet takes numerous turns to "warm up," though the resistances and enhancer take effect immediately.
- Death's Door: Replace Charms with Hexes as the second school.
- Deflect Missiles and Repel Missiles: Removed and made into a single brand for cloaks.
- Excruciating Wounds: Replace Charms with Hexes as the second school.
- Haste: Remove with no replacement. Potions and the wand are enough.
- Infusion: Remove and replace with Helm of Infusion, which provides the same effect permanently.
- Invisibility: Remove without replacement, ideally by making Cloaks of Invisibility somewhat more common.
- Iskenderun's Battlesphere: Replace Charms with Summoning. Alternately, remove and replace Amulet of Mana Regeneration with Amulet of Doubling, which automatically summons Battlespheres, replacing destroyed ones at full MP. Spells cost an additional MP when wearing Amulet of Doubling.
- Phase Shift and Shroud of Golubria: Remove and add a "Shroud" effect to Amulet of Dismissal. This shroud acts as the current spells, and is automatically regenerated at full HP.
- Portal Projectile: Remove and replace Gloves of Archery with Gloves of Volleying, which gives the pproj effect. Alternately, following ranged reform, remove without replacement.
- Regeneration: Remove without replacement. The amulet, brand, and TLA are enough.
- Ring of Flames: Remove and replace Ring of Fire with an Amulet of Fire. Gives the RoF effect (including Fire enhancer) and rF++ rC-. The amulet's resistances take effect immediately, but the RoF effect takes a number of turns to "warm up."
- Song of Slaying: Remove and replace Amulet of Harm with Amulet of Song, which gives a permanent Song of Slaying effect. After some number of turns, the counter resets to zero, but the player is constantly singing. On removal, the player continues to sing for ~100 turns.
- Spectral Weapon: Replace Charms with Summoning. Alternately, remove and replace with Amulet of Spectral Weapon (better name tba), which summons a permanent spectral weapon that cannot be killed but shares its damage with the player as before. On removal, player gets XP-gated Weakness
- Stoneskin: Remove without replacement, as the Amulet of Ice above fills the niche.
- Swiftness: Remove and replace Boots of Running with Boots of Swiftness, which can be evoked to provide the spell's effect. Alternately, leave it as a single-school Air spell.
- Warp Weapon: Replace Charms with Hexes as the second school.
Transmutationstl;dr: transmutations are made into toggleable spells that set your MP to zero, or removed as a spell school and turned into a god. Non-form spells are removed, and Necromutation is turned into an amulet.
I can think of two ways to "fix" Transmutations:
My first idea: transmutation remains a spell school, but its spells work differently. Casting a transmutation spell takes your MP to zero, and MP is not regenerated until the player leaves the form in the (a)bilities menu. The amount of MP required to enter a form is the same as its spell level, so you must have at least 5 MP to cast Blade Hands again. This retains the Tm background, and it's the idea I'm leaning toward.
Second: All transmutation spells and the background are removed and replaced with a God of Transmutation, which would slowly transform the player over time. Appreciates gaining skill in unarmed combat, and grants permanent forms, starting with Appendage at 0*-1*, a second Appendage at 2*-3* Blade Hands at 4*-5*, and the player's choice of Statue Form or Dragon Form at 6*. Active abilities include Sticks to Snakes at 2* and Irradiate at 4*, both of which have a moderate piety cost, though falling below a piety breakpoint does not exit your current form.
edit: Third: You could always make tmuts into a new dungeon feature, "Fountains of Transformation," with different forms expected at varying depths? Stepping into a fountain transforms you; stepping into it again untransforms you, but dries out the fountain? Starting as a tmut lets you begin the game with Appendage, Spider is found D:2-5, etc.?
With either of these changes, Necromutation is removed as a spell and the Amulet of Gourmand is replaced with the Amulet of Necromutation. Equipping and unequipping the Amulet of Necromutation torments the player; on unequip, they also receive the "Alive" status, which prevents the use of Death's Door or Borg's.
Furthermore, Sticks to Snakes and Alistair's are just removed. Ignite Poison, Petrify, Passwall, and Irradiate lose the tmut school; the earth spells get hexes instead of tmut, and no replacement is needed for Ignite Poison or Irradiate.
Obviously, this kind of sweeping reform is unlikely, but since I spent a lot of time coming up with this while my car was getting an oil change, I thought I'd share.
e: added a third tmut reform idea from downthread.