Akrasia said:
What attracts many GMs and players to rules light systems, IME, is a desire to stop 'sweating the details' (e.g. adding up endless modifiers, etc.), and 'get on with the game/story'. Hence they are less likely to introduce ad hoc 'fiddly' modifiers in particular situations in order to 'simulate' those situations better (what some people, e.g. Psion, refer to as 'fidelity'). Since the desired level of fidelity has already been achieved by the rules, for the most part, then IME GMs have not been any more arbitrary in their rules light games than they have been in their rules heavy games.
Actually, one of the things that turned me back towards lighter games was indeed my quest for better simulation. I started to realize that more rules & detail often didn't result in a better simulation.
As one example, in a real fight, there are fients & secondary attack modes (e.g. shield bash or using the butt end of a weapon instead of the business end). As with any rule, you have to find a compromise between simulation & playability. So, the simulation of these details yields to playability concerns. Plus, the player now has to know when to use these techniques. Often, the player doesn't know that as well as his PC should, making an even worse simulation. (Or the other way around: The player knows--by this specific set of rules--when to use certain techniques better than his PC should.)
By raising the level of abstraction, you end up with a better, if less detailed, simulation.
Remathilis said:
I have to agree on one thing: a rules-lite system becomes bloated quickly the more you have to adjuncate on the fly.
IME, lighter games don't get bloated with house-rules to reproduce the complexity of a heavier game. There'd be little point if that were the case. Instead, people playing lighter games are aiming for a higher level of abstraction. The extra detail, if desired, comes from imagination, interpretation, & description rather than from rules.
Remathilis said:
Otherwise, you are adding either house rules (skill systems, martial arts systems) or you are denying concepts (dex-based fighters).
CoC and other Rules-Lite (including my beloved Basic D&D) only really work well when you stick to archtype. If you don't mind your fighters as brutes, mages as weaklings, rogues who pick pockets and rangers who duel-wield, you're fine. But woe to those who stray off the path.
To me this is a different issue that rules-light v. rules-heavy. Risus is lighter than classic D&D or C&C, but it denies almost nothing!
I do think that, in some ways, classic D&D is a better game for denying some character concepts. But that's a separate issue from it being rules-light.
Re: different mechanics for different things: I think this can be a good thing, even though it tends towards rules-heavy rather than rules-light. (Though, oddly enough, many rules-heavy systems have a unified mechanic.)
Classic D&D used different mechanics for "to hit" & damage because that way they were simple to design, are simple to understand, simple to use in play, & give the results the designer wanted. Classic D&D used d% for thief skills rather than the d20 used for "to hit" & saving throws because the designer thought it was important to be able to graduate the abilities in increments less than 5%. Each side rolling 1d6 for initiative was choosen because it was the simplest way to get ties 1/6th of the time with an equal chance of either side winning the rest of the time.
When it comes right down to it, classic D&D (at least my favorite edition: c. 1981) has only a handful of mechanics that are all very, very simple. Not hard to get a grasp on at all. Most of us around here did it pretty quickly when we were about 10-12 years old. I've worked on unifying several of them before, but in the end, any gain from unification wasn't really worth it, IMHO.
(With a few exceptions, almost everything in classic D&D is roll above or below a target number on 1d (counting d% as 1d). Make it
nd & there are even fewer exceptions. While unifying on roll high or roll low
might be worthwhile, I don't see that unifying on a particular die type to be. I could probably argue that every dice mechanics in classic D&D is one of three unified mechanics. 3e has at least that many.)