Wednesday, 28th March 2012, 23:35 by Blade
Even with something like that, I don't think it would do much to differentiate the two races for standard play. Trap creation would still be a fairly minor aspect of an overarching strategy, and unless it was crazy op, it would often fall to the wayside in favor of exactly the same thing that already happens.
It's really a challenge to differentiate races based almost purely on apts. For example, consider an idea of two races, one with good apts in long blades and polearms, the other with good apts in m&f and axes, all other things being equal. One could say "They're plenty differentiated -- look at the weapon apts," but what it would come down to is one would kill everything with long blades or polearms, and the other would kill everything the exact same way with an axe or mace. In the end, a game with polearms will feel almost identical to one with axes, with a slightly different flavour (and some mechanics differences, but nothing big enough to note). Same thing with apts for, say, fire and ice -- whether you use throw icicle or fireball to kill all the dudes, they will still end up dead in almost the same way. A race could try go the "defensive juggernaut" route, but the player would still pick up offensive skills, kill dudes the same way they always have, and appreciate heightened defenses while doing so with nothing really changed.
To feel truly different from each other, races need to have mutations/special conditions (which many races do; the ones where it impacts the game in a meaningful way are sp, ce, dd, dg, ds, fe, gh, mu, na, og, op, tr, and vp, with arguably a few less or more) or very significant apt differences -- the difference between a deep elf and a minotaur, for example -- and halflings and kobolds (along with some other races) have none of this. All the flavour changes in the world will not change that playstyles will fundamentally not feel unique.
Another challenge is specialization -- if you make one race very good at a few things and not very good at everything else, almost every one of them will play in a very similar manner (see: ogres [although +2 spc helps with this], felids, merfolk, trolls, a few others). Further, there is less reason to use those playstyles with other races, because "if you want to do that, why are you not this race." This is fine to have for a few races, but if you have too many like that, it reduces "real" choices.
So...I'm not really sure what could be done with halflings and kobolds (and the other races with similar niches) to differentiate them further. Crawl only has so many niches, and they're all pretty well covered by the races out there. Without a drastic change to one or both, whether in apts or mutations, they'll still end up being very similar in all ways other than flavour. Would it be fine to keep them both anyway? Yeah; they have somewhat distinct niches, even if they're not as different as would be ideal. Would it be fine to cut one? Yeah. Crawl has too many races right now.
(note: I'm not sure how much sense any of this makes; it was much more coherent in my head. I hope that I still managed to say more than nothing in this huge block of text)