Intrinsics that you can gain from eating that do not give you some increment of a percentage (for instance, teleport control) are impossible to gain as a permanent intrinsic. Instead it will always time out.

In variants with percentage-based intrinsics, see invisible is no longer a binary attribute. Eating invisible stalkers now gives you various percentages of the intrinsic. While extrinsic see invisible still works like it does now, allowing you to see any invisible monster in line of sight, intrinsic see invisible shows you invisible monsters in line of sight within a certain radius from you. The radius increases with the percentage, possibly the square root of the percentage (so 64% see invisible is a radius of 8, and 100% is a radius of 10 - note that 100% still is less powerful than extrinsic see invisible’s unlimited range).

In variants with percentage intrinsics, intrinsics granted by one’s role need not be binary. For instance, monks tend to gain a lot of elemental resistances by leveling up, so rather than having those be all-or-nothing cutoffs at fixed levels, spread it out so that they gain a decent percentage of the resistance with each level near the original cutoff.

This would complicate the enlightenment display, since now it would have to disclose something like “You have 76% fire resistance: 45% from corpses and 31% from your priest levels”.

Intrinsic teleportitis is no longer binary; you build it up by getting the intrinsic from multiple corpses. With more of it built up, the random teleports happen more frequently (essentially, “teleport opportunities” happen at the same rate the currently do; if you have N% teleportitis, you have an N% chance of teleporting on each opportunity).

However, the effect wears off over time and eventually fades completely (with some message like “You feel less jumpy”, so the hero knows they can’t Ctrl-T at will anymore).

Extrinsic teleportitis remains the same, triggering a teleport at the same rate it does currently.

This implementation meshes well with a partial intrinsic system like in SporkHack or EvilHack.