if you are in acoustically good to excellent sounding rooms with minimal to no crowd noise, and you are happy with the omni sound you already have....and simply looking to upgrade your gear, i think your best bet is the DPA omnis (great sound, tiny size, easy to power, proven). however, if you can stomach a larger capsule, you go the active cables> Schoeps MK2S or AKG omni route...both of the latter having the added ability to run the rig with different capsules, with the AKGs being considerably less expensive than the DPA or Schoeps, with a proven sound that you can get a lot of samples to listen to.
the perspective of many of the replies here is louder concert taping with chatty/loud audiences, problems you don't have (if i understand your original post). given this, i would argue the Schoeps MK21 caps would do fine. a little more directionality/imaging than the omni sound you already like, but slightly harder to position properly if they are in a hat. as with anything, there are pros/cons and compromises.
good luck