With or without servo, I would never call the Gamma bass poor. With servo, I would go as far as calling it Stellar. Or Incredible. Tight, fast, low, and more than you could ever need. And you would never, ever feel the need for a sub. I've got a sub in another room that would keep up, but have never felt a need to use it.
That said, it sounds like you have some things to work out. A few suggestions that may seem out there. First, how is the surround foam? If it hasn't been replaced, it needs to be. Bill Watkins will do it for around $50 each. He just did both of my servo woofers. And since the dustcap material is intregal to the overall suspension system of the woofers, he is able to keep the original intact by using LF oscillations to align the voice coil, insead of removing the dustcap to align it manually. BTW, as of a month ago, Harmon still had 34 OEM woofers in stock. They show they are only for Betas, and the manual shows a different stock number for Beta & Gamma, but after pulling woofers from the Betas & the Gammas, I can assure you they are the same. Identical part numbers as well. In fact, the same part number that is still stocked at Harmon. Here's the best part. They are only $125 shipped! No servo woofers though, so treat those like Unobtanium. After looking closely at mine, I am sure I could make a regular woofer into a servo if absolutely necessary.
Second, between myself and my Gammas, and my friend with his Betas we have found OEM wiring problems with both. My servo (untouched) had a pair of the inputs wired wrong for left & right. His Betas were wired 180 out of phase at the speaker connector terminals on one of the woofer towers. Talk about lousy bass. It's very easy to check the phase of the wiring from speaker to speaker. Hook up a D-cell battery to the LF speaker terminals when the switch is in SERVO position and watch to see if the drivers push out or pull in, then do the same thing (same +/-) to the other speaker and compare.
You were mentioning running the amps full range. The servo box sends full range to the panels, so even in the manual, it tells you you can bypass the box entirely and run straight from the amp to the L-emim/emim/emit/s-emit (one less set of interconnects to degrade sound). The only thing that gets a crossover is the lows, which is done in the servo unit.
Have fun!