D&D 5E Natural Arcane Caster brainstorming

[Blue]

We have the Sorcerer as a natural caster, but what if I want to go even further? This is just a theoretical brainstorm, not to replace the Sorcerer or debate if there is a need for another class. Say we look at the vector from wizard with lots of selection variety to sorcerer with few spells but ways to bend them, and want to take another step in the same direction of about the same size.

So, what do we build? This is a brainstorm - I'm more interested in your ideas than critique of what I can think of. But let me throw some ideas out there just to build some momentum. Feel free to discard them or mine them for your ideas.

Don't have a good name, using Arcane Ace as a placeholder

Here's an option:

• A lot more metamagic options, with each Arcane Ace having more than a sorcerer. Can put multiple metamagic on a spell. Likely there are a few standards (that would otherwise be "feat tax") and then some customization options.
• High level slots like a warlock that are always cast at maximum level on short rest PLUS normal half-caster progression (that even stacks multiclass-wise).
  • Half-caster progression is somewhat to fill the niche Warlock invocations would fill while building on utility and low level spells that don't upcast.
• Sorcerer Points a bit like a sorcerer, but also short-rest recharge.
• Extra levels of a slot act like Sorcerer Points AS WELL as upcasting. So using a 5th level slot for a Fireball would not only be upcast, but also add 2 SP worth of metamagic for free.
  • Idea is just about everything is upcast. All the time.
  • Maybe cooldowns (or SP increases) to stop the same metamagic from being used again and again to stop spamming one spell+metamagic combo. Something too good becomes boring.
• Few spells known but across a wide spell list (or lists).
  • Hmm, base list, and then subclasses that add another list along with flavor. So one subclass adds the druid list and gives primal bennies, etc. A full list might be too wide, but with very few spells known it won't be a huge thing.
• Since only having a single concentration spell going doesn't work well when you restrict spells known a lot, one of the default metamagics is extra Concentration. Can't be the same spell or have any of the same targets as existing Concentration.
• Gets a reaction to attempt to negate parts of spells that target them (but not the effects on other targets), later becomes a redirect instead.

But really, I'd rather hear your ideas. So, whatcha got?