Ok, so now we've went from magic and martial should be different to excluding certain types of differences. Hmmm, ok, I don't think anyone is arguing a specific type of difference?
No. The argument is that it makes no sense for a specific type of simmilarity to be different. The argument isn't that Scry should behave the same way as stabbing someone with your sword. It's that shooting someone with a bow and shooting someone with a ray are comparable actions and should therefore be handled in a comparable manner. The different action resolution mechanic should reflect what you are doing.
And reliable magic isn't fundamentally different in effect from shooting someone. (Which is one of the core issues with D&D magic that makes it distinct from many worlds - the magic is reliable).
Which means that having different mechanics to do this is cluttered, ugly, and can easily create unfortunate complications that wouldn't happen if we used the same mechanic
to do the same thing. If we were doing different things - for instance unreliable ritual magic as opposed to reliable combat magic, there would be a good reason to use different mechanics. But two systems that do the same thing differently is bad game design.
Not an expert on GURPS, but... Don't different magic systems behave differently? If not... why are there different books such as GURPS Voodoo or GURPS Spirits?
GURPS Voodoo and GURPS Spirits are basically GURPS Ritual Magic. As such they are akin to the 4e ritual casting system rather than 4e combat. Which uses different mechanics to 4e combat. If you need to draw a pentagram and dribble candlewax for five minutes, that
isn't like throwing a ray of frost at someone. Or like shooting them with an arrow.
In short, GURPS Spirits is the GURPS equivalent to the 4e Ritual Magic system. If are trying to claim GURPS Spirits as different then 4e behaves the way you want it to. At which point your entire argument vanishes in a puff of smoke.
Spirit of the Century... I'll give you this one... but then it's one of those games, like Heroquest that purposefully goes for making EVERYTHING the exact same mechanic. I wonder how popular or mainstream it is? I don't think it would rank in the top 10 games... so I'm not sure how this particular game helps your case.
See: Dresden Files - licensed version of the same game. For a while the Dresden Files were in the top three sellers (behind only the two versions of D&D).
So yeah, I'd call that one pretty popular. Top 3 seller recently. And there isn't the supplement stream to keep it up there. We don't get Adventure Path Supplement #53, Races of Mystara, or Psionic Power 2 to pump up the number of books. Spirit's still a steady seller even after nine years.
WFRP3e... No experience with it at all.
WFRP2e and CoC... selective exclusion, got it.
Excluded because there is a purpose of making the mechanics different. The premise is that where the thing done is the same, the mechanics should be the same. WFRP 2e does something different - different blowback because you're messing around with Warhammer Magic. It's different becasue of the nature of the universe, not just because "it's magic".
Feng Shui... Again, a game I'm unfamiliar with... when was this game released? Is it still in print, how popular is it?
1996 IIRC. And no, it's not still in print.
WoD... Now here we go, finally something I know something about. In the Second Sight book each spell is basically it's own little set of mini-rules that vary from other spells (rituals). the basis is a dice pool... but magic is affected by the belief of witnesses, modified by magical connection, and limited as well as strengthened or weakened by the tradition the player picks. All of these are mechanics that seperate the mechanics for magic from the mechanics for a mundane skill.
You note what you list as differences. Differences
in the fiction. Which I don't think anyone disputes should be resolved differently. The magical connection is an inherent part of the fiction. The dice resolution mechanic is the same. I'm counting this as the same. The magic resolution system is the same. The difference comes from
what you are resolving. Which is as it should be.
You want another top 3 game? We've already had one (Spirit of the Century's reskin of Dresden Files). Try Marvel Superheroes.
OAN: What does wizards and casters and their second class cousins have to do with this discussion? You do realize different mechanics do not equate to better or more powwerful?
No. Mechanics being different for purely arbitrary reasons is an unnecessary imbalance. It's a pointless aesthetic flaw in the game that can lead to much more practical flaws.
If you want an actually distinct magical system that, for instance has blowback or relies on the nature of reality then those are different because the fiction is different. The case being made is that magic should not be different
for the sake of being different.
The essential fun from RPGs is the narrative built. Consider the AD&D sleep spell. Mechanically, it's only difference from a regular to-hit roll is that the DM is rolling it instead of the player. (In some early games, even this is not different, as DMs rolled all dice.) The mechanic didn't create the feel of magic -- the players and DMs created that by describing the narrative. How they imagined it was different.
I believe that for some people -- not all, mind you, but some --, the physical presence of a grid and minis/tokens diminishes the image created in the mind's eye. The map and minis serve as a proxy for the function of imagination; not surprising as this is their essential purpose. The imagination is relied on less to create a picture of the scene, because the map in front of the players provides instant expression of the effect. The sleep spell makes the mini lay on its side, or wear some kind of marker that says "Unconscious".
And for others the grid actively enhances things. It means we are automatically on almost the same page and there are far, far fewer questions we need to ask just to reach the baseline. A picture is worth a thousand words - and the battemap provides us with a blurry photograph we can all see and on which we can build.