Observation: the biggest reason why non-spellcasters like Barbarians suffer at high levels is because WotC builds mechanical synergies into the game, and many, many of these synergies are spells, so if you invest 20 levels in Barbarian you are giving up lots of potential spells, including high-level spells like True Polymorph.
Design goal: without removing any of a spellcaster's mechanical power, provide a roleplaying or setting reason why you'd even ever want to be a Barbarian or a non-spellcasting Rogue or whatever.
Solution: Break the campaign setting into Real and Not-Real areas. In Real areas, everything works pretty much in real life. The inside of a building is always smaller than the outside, your reflection is just a reflection and can never reach out and strangle you, black cats crossing your path don't really bring you bad luck, and faerie/vampire folklore is just superstition. None of that stuff is real. This is where PCs' home bases will tend to be, as well as civilization, shopkeepers, and a limited amount of political intrigue--but no dungeons and not very much treasure. Magical monsters cannot come to Real places or they cease to exist.
In Not-Real areas, also called Fable or Myth, all bets are off. Not only do magical creatures appear, and unlikely coincidences like stumbling across an ancient crypt stuffed to the brim with both undead monstrosities and treasure that somehow hasn't already been looted by someone else, but the DM will make your life interesting in other ways as well. Karma can come back to bite you, the inside of a dragon's cave can be far, far larger than its outside, genies can grant wishes, and faerie-tale logic applies.
Here's the catch: using magic breaks reality and transforms Real places into Not-real places, so magic-use is heavily stigmatized. It's not that you can't cast Zone of Truth in a fully-populated city, it's just that doing so turns the city basically uninhabitable by people who aren't prepared to get eaten by Unreal monsters. It's like contaminating the city with nuclear waste. Accordingly, spellcasters (who are always marked by a campaign-specific universally-recognizable physical characteristic, e.g. a brilliant-white lock of hair, and are referred to as Mythmakers) are stigmatized and generally unwelcome in society even if they aren't actually planning on creating any Unreality at the moment. They are dangerous.
There are also outlying Fringe areas, settlements which are mostly Not-Real but where the dwelling places (insides of homes) are Real, so people are safe from monsters in their beds at night but may occasionally have to send for help from adventurers (highly-expert people who are often Mythmakers) to deal with the Mythical problems threatening their livelihood.
Result: if you want more freedom to get involved in politics or society in Real places, pull non-magical heists, have a real job as an important person's bodyguard protecting him from assassins, etc., play a non-Mythmaker character like a Barbarian or a Samurai or a Rogue, or a Ranger who has never cast a spell (and so isn't marked as a Mythmaker yet), and hang out in Reality. If you want to do dungeon crawls and kill monsters, play a Mythmaker and hang out in Fable where everything is Not-Real. Or play a Chaotic Evil Mythmaker who uses illusions and stuff to disguise his nature and just doesn't care about the collateral damage to reality he's causing with his spells. It's all part of the same setting but everyone has a niche.
Design goal: without removing any of a spellcaster's mechanical power, provide a roleplaying or setting reason why you'd even ever want to be a Barbarian or a non-spellcasting Rogue or whatever.
Solution: Break the campaign setting into Real and Not-Real areas. In Real areas, everything works pretty much in real life. The inside of a building is always smaller than the outside, your reflection is just a reflection and can never reach out and strangle you, black cats crossing your path don't really bring you bad luck, and faerie/vampire folklore is just superstition. None of that stuff is real. This is where PCs' home bases will tend to be, as well as civilization, shopkeepers, and a limited amount of political intrigue--but no dungeons and not very much treasure. Magical monsters cannot come to Real places or they cease to exist.
In Not-Real areas, also called Fable or Myth, all bets are off. Not only do magical creatures appear, and unlikely coincidences like stumbling across an ancient crypt stuffed to the brim with both undead monstrosities and treasure that somehow hasn't already been looted by someone else, but the DM will make your life interesting in other ways as well. Karma can come back to bite you, the inside of a dragon's cave can be far, far larger than its outside, genies can grant wishes, and faerie-tale logic applies.
Here's the catch: using magic breaks reality and transforms Real places into Not-real places, so magic-use is heavily stigmatized. It's not that you can't cast Zone of Truth in a fully-populated city, it's just that doing so turns the city basically uninhabitable by people who aren't prepared to get eaten by Unreal monsters. It's like contaminating the city with nuclear waste. Accordingly, spellcasters (who are always marked by a campaign-specific universally-recognizable physical characteristic, e.g. a brilliant-white lock of hair, and are referred to as Mythmakers) are stigmatized and generally unwelcome in society even if they aren't actually planning on creating any Unreality at the moment. They are dangerous.
There are also outlying Fringe areas, settlements which are mostly Not-Real but where the dwelling places (insides of homes) are Real, so people are safe from monsters in their beds at night but may occasionally have to send for help from adventurers (highly-expert people who are often Mythmakers) to deal with the Mythical problems threatening their livelihood.
Result: if you want more freedom to get involved in politics or society in Real places, pull non-magical heists, have a real job as an important person's bodyguard protecting him from assassins, etc., play a non-Mythmaker character like a Barbarian or a Samurai or a Rogue, or a Ranger who has never cast a spell (and so isn't marked as a Mythmaker yet), and hang out in Reality. If you want to do dungeon crawls and kill monsters, play a Mythmaker and hang out in Fable where everything is Not-Real. Or play a Chaotic Evil Mythmaker who uses illusions and stuff to disguise his nature and just doesn't care about the collateral damage to reality he's causing with his spells. It's all part of the same setting but everyone has a niche.
--
I could not love thee dear, so much,
Loved I not honor more.
I could not love thee dear, so much,
Loved I not honor more.
