Yeah, my first thought was that carbon-benders are extremely powerful, whereas all the [synthetic element that doesn't exist in nature and lasts a fraction of a second]-benders are essentially muggles.
(Which actually would be a cool explanation for the existence of muggles, they're the people born with the potential to control element 300 or something.)
But I think the idea in the OP was more of a metaphorical system based around the properties of the elements, rather than element-kinesis. Even Avatar does this a bit; air-benders are really good at dodging like a leaf in the breeze, water-benders can heal because water is soothing, earth-benders can echolocate because earth is good at conducting vibrations, etc.
Aerb, the world of Worth the Candle, stands out as a prototype I think - a setting with a ton of different magics, like Gold Magic or Bone Magic or Gem Magic, each based on different metaphors and properties of the thing in question. (Gold is valuable so Gold Mages get more powerful the more gold they hoard but risk being undermined by their greed, Gem Mages shoot lasers based on the refraction of light through their gems, bones form the underlying skeleton of the body so Bone Mages can pull a creature's innate abilities from them, etc.)
So like, a xenonmancer wouldn't necessarily control elemental xenon, they might channel it's unreactivity to become immune to poison and acid (a shared power of all Noble Gas mages?) and it's fluorescence to shoot beams of blue light.
The more I think about this, the less unwieldy it seems, since the properties of elements are fairly well-structured. (A xenonmancer is a noble gas mage and a fluorescent, plus probably some stuff based around density and being a gas at human-livable temperatures, etc.) If you really wanted each elemental school to be totally unique magical schools in ways that are somehow still convincingly tied to their properties, even allowing for cultural properties like "gold is valuable", that would be harder.