I have HTC Incredible 1 (now wifi only) and replaced it with Moto Razr Maxx. I too immediately noticed that the Maxx appeared to have less sensitivity. So I installed the app "wifi analyzer" on both phones.
What I see is that the Maxx typically shows one less bar than Incredible when the signal strength meter shows same value. However, the Maxx typically runs from 3 to 10 dB less strength at the same location, once I get more than 15 feet away from router! This is really terrible: 3 dB means 1/2 the power, 10 dB is one-tenth the power. Furthermore, watching the power meter on both devices, I see that while standing still, the meter on the Maxx fluctuates by as much as 10 dB units, but on the HTC it stays nearly constant.
I think Motorola really blew it with the wifi.