Okay, so here's the thing about skill aptitudes: by Crawl's official standards, they are a bad design.
- Code:
Major design goals
* challenging and random gameplay, with skill making a real difference
* meaningful decisions (no no-brainers)
* avoidance of grinding (no scumming)
* gameplay supporting painless interface and newbie support
Minor design goals
* clarity (playability without need for spoilers)
* internal consistency
* replayability (using branches, species, playing styles and gods)
* proper use of out of depth monsters
Avoiding no-brainers is a major design goal.
The whole point of the skill aptitude system is to create no-brainers. When a species has unequal aptitudes in weapons/spells/melee vs. ranged combat vs. conjurations, you obviously default to the option with the highest aptitude, assuming the options are balanced against each other in the first place. So there are only a few things that could potentially make skill aptitude a reasonable feature:
- Skilling options aren't balanced in comparison to each other. For example, back in 0.5, maces were total crap and if you had +0 maces and +0 axes you'd always use axes. But that's an obvious balance problem in its own right that needs to be corrected for all species, so trying to fix it using a species-dependent system makes no sense.
- All of a species' aptitudes are the same, so you have species that are generally better at all skills and species that are generally worse at all skills. Mummies vs. demonspawn vs. demigods vs. humans are almost an example of this. But then why are there separate aptitudes for different skills? If you're going to do this, there should just be one aptitude that controls all skills.
- A species has some special feature that makes a skill abnormally useful/useless compared to other species. Ogres and trolls are good examples; maces skill and unarmed combat skill are abnormally useful to these species. If ogre's maces aptitude was lower than all its other weapon aptitudes, and troll's unarmed aptitude was lower than all its weapon aptitudes, then the aptitude difference would actually help balance them. In these examples, that's literally the opposite of the status quo (ogres' maces aptitude is their highest one, and troll's unarmed aptitude is their highest one), but hey, that could change.
Since this pretty much never happens in the game currently, I think the devs regard it as a clumsy approach to balance or something like that. And if that's the case, I'd agree with them. - You are willing to sacrifice meaningful decisions (a major design goal) to make species more different from each other, presumably for replayability (a minor design goal). This isn't a great trade, which is why you see it less and less often these days.
I believe at least some of the DCSS devs basically agree with this, because when skill aptitudes change, it's usually either to reduce their impact (because their impact on the game is bad), or to compromise a major design goal (no no-brainers) in deference to a minor one (replayability) or something else that isn't even a design goal (flavour).
The result is that skill aptitudes that actually do something are mostly restricted to older species like HO and HE and DE and Mi, which a lot of people don't really want to change because "
human with shallower strategic decisions" is their entire design, and getting rid of their skill aptitudes makes them just "
human with
sexier ears" which would probably
get removed from the game pretty
fast. If you want to add a new species with lopsided skill aptitudes you have to first attach some gimmick to it so it's a candidate for addition at all, and then push through the stupid aptitudes on the basis of flavour or replayability. The success rate of this is actually pretty good, it worked for Fo/Gr/VS and even for Op's stealth aptitude.
I specified "skill aptitudes" here, but MP aptitude probably has a similar problem. HP aptitude is fine. Experience aptitude is basically redundant with HP/MP aptitude, since the only consequential effects of XL are HP/MP and occasionally spell levels.