Be sure that you have broken in and set up everything correctly. Phono stages and carts can take a long time to break in especially if there are transformers involved. Start by reading the TWL thread on Rega arm setup (Forums: Strange Tonearm Tweak. Long). Search the other threads as there is an incredible amount of good info among the prognostification (swatin' flies & tellin' lies). "Phono Burn in" & granite audio and reverse RIAA stuff is worth reading etc etc....
Verify VTF & VTA of your arm. Groove tracer arm weight, Cardas (or better)tonearm cable, Funk Firm platter (or others) are other possible upgrades as you need them.
Cartridge wise, if after you check everything and you still want more and you are now knowledgeable with cart setup, try the Denon DL-103 or Dl-103r. "Start with the Dynavector p75 set at 470 ohm, 60db..... great midrange, like a poor mans Koetsu slightly less lush, koetsu may have a touch better flow and romanticism, but I think the denons bass is probably better". Experiment, if needed, with the other p75 settings until you have dialed in the best sound.
There is plenty more gold to be mined at the P5 level
Enjoy your music!%!$!
Jon