I am curious as to what some of your DVD-A / SACD discs are. I do have a few that leave me wanting more in the bass dept. For the most part I am very satisfied with the amount of bass in all of the mentioned formats. (I am a classical bass player so it is very important to me too)
I realize all formats use all 5 channels, to me several of the dts cds I own don't sound any different than a CD being played back in 5ch stereo. I am quite aware that the mastering of the disc is to blame for this. It just seems to me it is more common for dts discs to be mastered this way.
I will say one think I don't like about dts cds, they cost $25 on average. A bit steep if you ask me.