Joined: Thursday, 10th May 2012, 03:29
The key feature is the perpendicular intersection of diagonal, single-tile halls which means that only one enemy can hit the player, and furthermore, only a single enemy can see the players. The others cannot summon, smite, etc. This is a rare layout, and most often it is created by players themselves. These "killholes" are frequently employed against draconian packs in Zot and in Elf:3, but are ideal for engaging any group of enemies.
Most player races can create these layouts using strategic consumables (wands of digging, disintegration, mostly. IOOD is an exception which I'm ignoring) and as such must choose the most appropriate time when entrenching themselves in such a structure would be most helpful. Formicids, having infinite digging, should dig these as soon as possible upon entering a new floor and drag enemies back to the safe spot. This recalls the idea of player-created traps, which has been dismissed on the basis of the tedium that setting up an array of traps and dragging enemies across the map to step on them would have.
In fact, the status quo is even worse! Because many of the game's substantial threats aren't speed 10 melee-only monsters, it's handy to have one of these layouts nearby to entrench oneself in as quickly as possible. So Formicids should optimally dig many of these structures every floor! This is clearly a very tedious strategy to put into practice.
I propose one solution and then will list a few others which won't work. Formicid digging should be made into a strategic resource. The player will have a finite quantity of dig "charges" which is replenished by gaining XP, reintroducing the strategic considerations in digging "killholes" which other races face, but giving the ants a distinct advantage.
Proposals which will not improve the situation include increasing the hunger cost of Fo digging, increasing the turns taken for each dig, decreasing the turns taken to 10 aut per dig, introducing more monsters with the dig spell. One radical proposal which might be worth discussing is the removal of dig entirely, but that's a larger issue.