If you're anything like me, You always want what you haven't got. We've had an Omnia 6, 3fmt, and Omnia.fm. They sound fine, but what you have is one of the best, you should easily sound competitve. Just a matter of finding out what works.
When you mention muddy, thats exactly what I first thought when setting up ours. By slowing the AGC you start hearing nuances that we're swallowed up before, plus it handles speach and Pianos much better.
Rock-LOUD (or dense) and slow the release time of the AGC. We have a huge problem with uneven levels into Nexgen, but the preset will be driving the multi-band system enough, with MEDIUM release time, it will still recover fast enough, and their shouldn't be any holes in the program unless it falls below the gate of the AGC. Infact I belive you can adjust the AGC gate and Multi-band gate individually. Try lowering it for the AGC if you find your programming falls away often.
When you mention muddy, thats exactly what I first thought when setting up ours. By slowing the AGC you start hearing nuances that we're swallowed up before, plus it handles speach and Pianos much better.
Give it a go