Many of us are not fans of auto room equalization for the entire audio spectrum. I believe you will get better results with room treatments and equalization only at low frequencies. For that reason I applaud Paradigm for offering a bass only room correction option for those who don't want to use auto room equalization.
I don't know if I would call my home theater modest, but I still like to spend money how it will most benefit the performance of my system. I bought TWO subs (SVS SB12-NSDs) and a Velodyne SMS-1 Bass Digital Room Correction for less than $1500.
That said, I completely agree with you. Paradigm makes great speakers (I own lots of them!) and I wouldn't mind having a couple of their subs with the PBK, but for what I get I don't think they worth the money over other brands. If I was going to spend that much on a sub it would be a JL Audio.