Saturday, 4th February 2017, 00:00 by ion_frigate
"Just walk away" is precisely equivalent to "park them up a level," unless you want to have to deal with autoexplore and autotravel being broken all the time. These aren't oklob plants - they're speed 10 monsters that will attempt to follow you. Even if their habit of blinking means you'll eventually lose them, it's still tedious as hell, and still prevents you from using autoexplore on that level.
I've been playing since 0.4. In that time, I have never once found a standard crimson imp to be anything resembling "fun." Fighting them feels like fighting the shitty high-AC, low-damage HP buckets that infest the latter half of NetHack. They force engagement but rarely put you in any actual danger.
Honestly, crimson imps' best moment was when they could pick up a bow and annihilate you with it. I'd suggest removing the regen, and guaranteeing them a weapon (one that has a decent chance of being a bow with arrows). Melee imps would then be an early introduction to blink frogs, while ranged imps would help teach the player that having some sort of ranged weapon of your own is a good idea. One could even make them appear first individually, and then in groups, as happens with gnolls and ogres.