I don't actually think "roll to cast" is that fundamentally important in the skill vs. spell capacity question. They have different resource expenditures, generally time vs. limited charges, and it's pretty easy to modulate access to them, thus that having a lot of spell ability limits broad skills. If anything, I think low level utility spells often represent a better core gameplay loop than skill checks do.
Just to clarify, I would not call my homebrew system’s approach “roll to cast”. As I understand it, that’s usually about using a check to see if the spell happened (such as mentioned by
@DaedalusX51 in
post #24 for DCC or how Shadowdark handles casting or a myriad of other games). I’m just having spells use skill checks like combat specialities use skill checks like how other actions use skill checks. The difference from a spell is what gets used as the method (i.e., your Mage rank versus some skill or speciality). Making it an extension of the skill system avoids problems like the classic
knock spell where it just succeeds, making having someone who can pick locks pretty pointless.
Skills are nearly always rolled reactively; a problem or obstacle happens, you roll a skill check to see if it affects you. Spells are proactive; the problem happens, you decide if you want to spend a resource to overcome it. That same thing expands to agency in general, skills rarely provide any ability to frame or alter a situation while spells have lots of declarative text that lets you do that.
There seem to be a couple of issues at play here. The first is granularity. If skills are just about whether you do a thing, then their ability to affect the overall situation is going to be limited. Spells, on the other hand, tend to tell you what happens. They give the players the ability to assert control over the game in a way that skill checks lack.
The second is that skill checks are being made reactively. The player may be setting up the situation that results in the check (“I sneak over there! <gm> Okay, roll Dexterity (Stealth)”), but they don’t have a lot of control over what happens. As you observe, the spell caster can proactively address the situation (“I cast
invisibility! <gm>Okay, you’re insivible now.”).
The way I handle this in my homebrew system is by making skills more effectful and intentional. Instead of having checks called by the referee, the player sets stakes. What I mean by “stakes” is they say what they hope to accomplish. After stakes are set, the player specifies the method (skill) and approach (attribute), and the referee indicates consequences (explicitly, but implied ones are okay as long as they’re obvious). If the roll succeeds (even a Mixed Success), the player gets what was at stake. The referee cannot screw them out of it. That should give skills more oomph like what spells have had traditionally (though obviously stakes need to make sense and can’t be stupid stuff like jumping to the moon).
I should note this isn’t a new approach. It’s inspired by other games. I think it could be adapted to D&D, but I expect you’ll find some people who like or prefer the way things work currently, and it won’t work well with certain types of play (particularly those where having the DM curate the experience is important and desired).
There's a lot of hacks that would make sense to put more abilities in the skill system that steal some of that gameplay from spells. Imagine say, a rogue with a pool of "thievery points" they can allot to increase skills checks so they can hit specific DCs, or a specialist character that can assign a floating skill bonus each rest to change their capabilities, or a berserker that can overdrive some skills for X period of time and risk fatigue...there's a lot of different resource models you could layer on top of a skill system.
In my homebrew system, classes in the expert group (such as thieves) can spend MP to add an extra die to their roll.
Pretty much everyone is going to do some bits of magic (except for barbarians, who eschew magic and have no MP and can never have any MP). That’s just how the setting works (if it’s magical, it uses MP; if it uses MP). The plan is for various classes to interface with it in different ways, but right now there are only the ones we need to play and a list of class ideas without any mechanics attached.
I blame a lot of my idiosyncrasies on a 3e entry into the hobby. It feels entirely normal and natural to me that skills should largely define their effects in player facing material, and the real design question was what those abilities should be and at what rate they should be delivered to characters. I'm still baffled by how comfortable everyone is with just making up a DC. I would have once upon a time called an RPG without an attempt to spell out the applications of skills as an incomplete product.
My first D&D was also 3e, but I missed most of the culture of play surrounding it. I played with a group that (I now recognize) was mixing 2e and 3e. Their game was also almost pure hack and slash, so other stuff tended not to come into play. It was certainly jarring the first time I actually had to RP a situation. After a few of us split off, we just did our own thing. What exposure I got to ideas outside of our group was from discovering OSR stuff online (like Grognardia), which influenced my thinking on how play should go.
