I'm relatively new to tabletop gaming in general, so this just the idea of homebrewing a class at all might be biting off more than I can chew in a big way, but I've had an idea for a campaign setting for a while, and with this setting comes the need for a couple of different classes that I don't think fit perfectly into a specific official class. In my setting, there's a race that has lost its affinity with other kinds of magic but can channel magic specifically relating to fire through dance. All of their spells would be flame-based, and they could fight either armed or unarmed, and then choose between the paths of light and shadow (one of which would bestow healing effects and possibly deal some radiant damage while the other would cast illusory spells that could feasibly be achieved with fire and *maybe* some cold damage because that's the absence of heat). I haven't decided if it should be a full caster or a half caster due to the limited pool of spells, the latter of which I suppose would allow for more utility in melee. I was thinking it would make the most sense for the class to use dex as their spellcasting modifier. I assume the reason nothing like this already exists in DnD is that this would allow the caster to forego their mental ability scores altogether. Would it sound more balanced if the caster's spellcasting mod was 1/2 (CHA + DEX) mod? What would be some good classes to base this class on and pull features from? I assume a couple homebrew flame dancer classes probably exist already, but I always question other people's homebrews. Has anybody had good experiences with one of these homebrew classes?

Yeah I think if it's a performance related casting, it makes sense and things would be a lot smoother if they used CHA to cast and then maybe you could key uses of class features to DEX. Going half and half over two stats would just be really messy.

DEX is just really strong. Having one stat cover your AC, weapon attacks, and casting is probably too much. Even Arcane Tricksters need INT and Hexblades need at least some DEX. You might be able to give it weak class features to compensate, but that doesn't seem like a lot of fun.

I have worked on a dancer subclass for rogue, but haven't tried to make a dancing caster. Sounds like a Bard subclass to me.

So, that concept sounds like something that could be flavored out of the new Way of Mercy Monk. It might be worth using them as an inspiration. As for why there are no dex casters, You've more or less hit the nail on the head. Str, Dex, and Con are all physical stats Wis, Int, and Cha are all mental stats. Magic is traditionally tied to mental especially the controlled application and manipulation of magic. That being said, there are some magic things that are related to physical stats, most notably some of the barbarian Storm herald Aura's being biased on Con at the determent of it not really being that manipulatable. If you are doing a combination of Melee and Spell casting, secondary caster is probably the way to go. There are some primary caster subclasses that are also melee biased but they are very hit or miss (I'm looking at you Valor Bard) especially if you are specializing and building something with a very clearly defined set of subclasses. I myself have not used anyone else's homebrew flame dancer classes.  

Now we move on to the part where I tell you about what I think and not about the questions you asked.

• Frankly, You could probably do this by making it a subclass of something that already exists, possibly Bard, Druid, or Artificer. Especially if you have never homebrewed a class/subclass before.
• Also before even that, you could take the mercy monk and homebrew some reflavoring of it to change the damage types and use some of the optional rules for monk to allow for the use of weapons. You can always flavor the way your character moves as you make your actions. 
• Homebrewing a class is very difficult especially if you want to do something that is actually balanced. You should introduce or expand on a mechanic that is in the game in a way that make the class unique without being limiting for subclasses.

All that said, don't let me stop your fun. Id love to see what you come up with, I just have hesitant optimism with the concept that you put forward, because it seems limiting as an actual class. 

What you said about the monk makes sense. I kinda started thinking about abilities and such and looking through all the current classes and I keep pulling monk more often than others. And yeah, it would probably be confusing to have to consider two stats for your casting. Half-caster does sound like the best way to go. Then the class abilities can have more flavor. So I guess the plan moving forward would be to compare the number of spells available at each level for ranger and paladin and adjust accordingly, then give them a similar number of abilities as they level up. I assume that the monk's Ki abilities don't quite equate to the level of power that comes with spellcasting. I've scrapped the light/darkness subclass to allow for more versatility for the character and decided to focus on three fighting styles instead- proficiency with unarmed, one-handed martial weapons other than whips, or whips.

Does this sound decent as a class feature?

The Flame Dancer treats active movement as his arcane focus. In order to cast spells, he must be actively moving and dancing. This requires that the flame dancer be able to move into an adjacent square while casting. He provokes attacks of opportunity from enemies he is adjacent to unless his movement is into another square adjacent to this creature.

Additionally, their spells require no verbal components. If a spell requires a verbal component, a somatic component is instead required.

So basically that would mean that as a spellcaster, he's immune to spells like silence and the like.

So... From what I gather, you want this character to be an agile fire caster that channels their magic through dance... My initial thoughts went to the monk aswell... But it sounds like the main focus here is caster with an addition of agile grace.. I don't think you should be trying to fit caster features onto a monk, there's no need when there are already several caster classes to use as frameworks.

Furthermore... I wouldn't recommend going with half caster if you're looking to base things around fire, which will probably often mean offensive spells.. I think half-castes are best at buffing their martial prowess and utility rather than actually throwing damaing spells... because those spells will feel underpowered and weak when you finally access them... Where as utility and buffs scale far better.

I really think you should consider making this a bard subclass. Charisma and Dex are very much bard-like stats, and you have the bardic inspiration feature to play around with...

So consider something like this.. Give your subclass something similar to the bladesong feature from the bladesinger, Once this "flame dance" is activated the bard has a list of spells that now only require somatic components and which they can spend a bardic to cast as a bonus action by spending an inspiration die or something. (leaving the full action open for the attack action)..

Alternatively you can make acivating the flame dance itself cost an inspiration die and add a number of "dance moves" to pick from which can be used as a bonus action while the flame dance is active.

Loose ideas, but I think you'd be far better off making a subclass than starting from scratch.. balancing is hard.

I agree. Given the changes that you made to your concept, a bard subclass makes sense. You can have a choice of dance styles within the subclass that allow for your different weapon focus. 

You can still use some of the monk stuff as insparation, I know that drunken fist has some stuff that allows the redirection of missed attacks and avoid attacks. If the whole class is baised around melee and spellcasting, it might be worth putting in some ability that increases mobility. It doesn't nessesarily need to be incresed movement speed, but being able to, say, move without provoking opportunity attacks in certain situations. 

An expanded spell list might also be something worth looking into. I don't know for certain, but I think bards have a very limited access to fire baised offensive spells. Unless you wanted to do something simmilar to divine smite where you spend a spell slot to additional dice of fire damage to an melee attack.

I kinda understand why ppl suggest monk based classes. But you might want to differentiate between 'forms' and dances.

Picture Avatar world where people's strength of elemental bending is based on understanding and performing the 'forms' this would fit the monk archetype and could be based on that.

If dancing is the source of the 'power' then I would say the strength would come from how well the dance were performed. As dance is a form of entertainment then CHA based, bard, would make sense as the base.

You can create a subclass based on pre-existing class. Creating one from scratch would be a headache for balancing purposes. Unless you only wish for NPCs to have this class..