I've been a DM for about 3 years, and have predominantly run one-shots and short campaigns in DnD5e and PF2e. I have a player who persistently builds primary caster based characters, but then won't do anything in combat but "I stab it with my dagger." They rarely use cantrips, and basically won't cast a leveled spell unless I suggest it immediately before their turn. They seem to enjoy playing despite the fact that they're far too squishy to be a front-line melee character and don't utilize most of their class features. I've talked with them explicitly about how their play style seems to be discordant with the kind of play they want to do, and that maybe next time they should try a paladin/champion or a fighter/rougue subclass with some minor casting. They agreed at the time that sounded like a good idea, but low and behold showed up to the next one-shot with a primary caster, and over 3 hours of play and 3 combats never cast a single spell, including a cantrip.
I enjoy playing with this persons as a whole. They are engaged in the fiction, and are particularly engaged during exploration activities. They tell me they also find combat quite fun, and they are requesting I run a mega dungeon in the near future.
As a general rule, I like to let people play how they have the most fun, but issues have arisen with this play style. Namely, all of my TPKs have been associated with this player charging a squishy character directly up to a significantly stronger villain and continuing to stab it with a dagger until they went down, significantly hindering the party in the action economy and resulting in a TPK. I feel I have to intentionally weaken all of my encounters to keep the party feasible in the face of such mechanically poor combat choices.
What else can I do to help drive this individual towards melee builds, and/or help encourage them to change their play style to better suite the caster classes they choose?
There’s really no right answer here and I don’t think it’s something that we can work through without that player involved in the conversation. It’s not that they don’t know better, it’s not that you haven’t helped them, it’s not that you haven’t made suggestions, and they’ve been doing this for 3 YEARS??? I’m sorry, but this is above my pay grade. I am almost certain there is some detail that I’m missing because this makes zero sense. I have played with veterans of all walks and ages, new players who are 8 years old, new players that are 60 years old, and everywhere in between. It just doesn’t make sense unless there’s more to it.
Sit down with the player again. Ask why they don’t use cantrips. Leave the leveled spells aside for now (saving them forever is a problem, but an understandable one). Continue to remind them every combat, every turn, every time they take out their dagger. I know you said your group doesn’t know the rules well, so maybe it’s time to learn (3 YEARS???). Cantrips and weapons work exactly the same, so I don’t know how “not wanting to engage with the mechanics” has anything to with it. There’s something going on and I can’t be sure what it is without talking to this player themselves
It's not quite 3 years. I've been DMing for about 3. This player has been playing on-and-off for about 1.5. I have complicated the rules a touch because in the last 8mo or so I've switched to PF2e. I mean this problem in specific isn't that system specific, so I don't think that really excuses it.
But all-in-all you're right. The most effective answer is find another group that is more invested in the game. I'm moving across the country in a few months, so I guess I should just ride the issue out a little longer and then move on, which is a huge bummer. I guess in the meantime I'll try and remind them more regularly and once again have the conversation about "Why?"
Thank you
Remind them every, single, turn.
“Really? Your dagger? Not your cantrip?”
“Oh yeah, I always forget about those”
If they prefer to use it for thematic or aesthetic reasons, they’ll tell you and the mystery will be solved. Maybe there’s a class that does what they want and you can push them towards it. Or maybe they really are just that forgetful and they just need to be reminded every turn. Consider giving them a character sheet that more obviously shows what they can do. Action cards, spell cards, stuff like that might help too. But ultimately, just don’t let them make a dagger attack. Just stop them and present the better option EVERY TIME. You’ll learn one way or another what they want because they’ll go with it or resist it
And I’m not necessarily saying to find a new group (although it seems like you’ll have no choice since you’re moving). I’m just saying, I cant imagine how you could keep playing with this person and no one at the table is making suggestions on how to play their turns. My players strategize about each others’ turns constantly. It’s a bit meta-gamey, but they’re newer and don’t know all the mechanics well so I never stop them. In fact, I try to help them find the course of action that will make them feel the coolest or the most useful without outright telling them what to do
My table tends to not metagame at all, even in situations I really wish they would. I think of all the answers I've gotten, this is the most reasonable and actionable answer. Just remind the player more often. I'm gonna have to come up with a good way to not sound like a condescending asshole because this is the only player I'm going to have to do it to. It just sucks cause it's one more thing I've gotta do while running combat. But that's life I guess