The cartridges Jmcgrogan2 listed would provide more of what you're seeking, though I have my doubts that the money they cost would be well spent. Your tonearm would not let you hear everything a UNIverse or Titan i can do. Not sure about your phono stage. It would help if you'd list your system...
Regardless, I'd advise several additional, no-cost adjustments before you drop serious money on a new cartridge. High end vinyl reproduction is not a plug-n-play proposition, as you've just learned. User involvement with trained ears is the only way to achieve optimal performance with gear at this level. In addition to the correct impedance loading that you just discovered...
1. Clean your stylus
If your stylus isn't properly cleaned after EVERY side it will accumulate a layer of burnished-on crud that will dull highs and micro-dynamics. If you aren't using a Magic Eraser after each side then your stylus almost certainly isn't clean. Search this forum or VA for details, how-to's and testimonials.
2. Set anti-bias (anti-skating) to "zero". Leave it there until you've accomplished #3. You may find you don't need any, or need far less than you're using now. Excessive A/S has exactly the deleterious effects you desribed and with some cartridges *any* amount of A/S is "excessive".
3. Fine-tune VTF
Your symptoms sound like the classic effects of marginally too-high VTF. Try reducing it by small (.05g) increments until you hear mistracking on tough-to-track passages. Then move VTF back up in tiny (.01g) increments until tracking is clean, high freq's are still clear and bass has some weight without thickness.
4. Play with VTA/SRA
Not easy with your arm, but your symptoms could indicate that the arm base is slightly too low.
If all this fails to achieve the sound you want, only then would it make sense to explore a new, high end LOMC. You'd have to do all these adjustments (and more) with a new cartridge anyway. You might as well learn how using a cartridge you're already familiar with.
Good luck!
