1. That was true for me too until I got an Electro EMC-1 MkII.
2. Especially true, and one of the reasons why Stereophile Class rank is spurious. Reviewers evaluate speakers IN THEIR ROOMS...not a controlled reference space.
3. Like Judit, I use a Pass pre/amps to entirely successful, non-grainy effect.
4. Wadia's filter algorithm DOES roll off the top octave noticeably. If that pleases you (especially with Redbook), then that's understandable. The EMC-1 is spectrally flat AND musical, by comparison.
5. Don't know. Guess it's a function of how well the DAC's filters synergize with your system.
6. A GOOD amplifier ends up being a good investment. A budget favorite like the Audio Refinement Complete for $1k is an outstanding integrated, while some $$$ separates sound, well, let's say less good.
My budget audiophile 2ch system I just built for a friend comprises:
NAD C541i ($400 discount new)
Audio refinement Complete Integrated ($700 used)
(Audio Refinement Complete Tuner ($450 used))
Spendor S3/51p ($800 used)
Plateau V23 stands ($200 discount new)
Canare Starquad speaker cables...to be upgraded to Blue Heaven after he "gets it". ($50 new)
Blue Heaven IC ($100 used)
(Canare IC for tuner ($20 new))
3 PCs made by me from belden 83802 ($200)
Total: under $3k, including FM.