A proposal for diminishing the effect of alchemy in NetHack.

Currently, in NetHack, nearly every potion of healing and extra healing is
saved to alchemise into full healing. It's difficult to use them as
emergency items, and even if you do, you're hurting your prospects in the
late game; conversely in the late game the character can have astronomical
numbers of HP, limiting challenge.

I propose the following:

The effect of a diluted potion is, where that can be made to make sense,
halved. Durations are halved for potions like levitation, the XP gained
from gain level is halved, etc; and most pertinently, the healing and max
HP gained by drinking a diluted potion is halved. (It is then desirable to
slightly tweak the relative effects of healing and extra healing such that
alchemising a healing into extra healing doesn't actually make it
worse...)

When diluted potions are dipped and undergo an alchemy reaction, their
quantity is halved. When a diluted potion is dipped into, the quantity of
potions converted is halved.

This means there is no max HP benefit to be had in alchemising a potion of
extra healing into one of full healing. To have the same effect on healing
vs extra healing, increase the max HP gain from a blessed undiluted potion
of healing to 2. (If blessed EH gave 4 max HP, alchemy would become
precisely max HP neutral - I'm not advocating this, just observing it.)


I also propose the following, not strictly related to alchemy:

Give an XL-dependent bonus to the healing from healing and extra healing,
keeping these items relevant even later in the game. (This could provide
the tweak to the relative values of healing and extra healing mentioned
above.)

Limit max HP gain from all methods, with some combination of diminishing
returns and a hard cap. I suggest this limit should be about half a fixed
quantity and half an amount proportional to XL - this means that gaining
levels on non-casters gives more utility (rather than just being a way to
meet more arch-lichen) but in normal play, players are unlikely to find
themselves incentivised to stow away nurses etc for later.

More radically, outside the scope of the alchemy proposal, and needing
some UI work, allow using consumables directly out of a container in
inventory, taking 2 turns (ie, getting the benefit of the consumable
immediately with no risk of it being destroyed, but still taking the time
it would take to apply the container and then use the consumable). The
rationale here is that it's presently quite hard to use consumables in
an emergency.