I guess the issue I was running into is the type of bass. Let me reiterate. As Burchardt points out, they are shooting for flat / neutral response in mk ii so the bass (60-200 hz) is not boosted. As also explained by @vthokie83, the designer removes the bump in Mk I to exchange more accurate sound in Mk II which makes sense as the boosted bass tends to colorate midrange. One could also observe the boosted bass in Dynaudio Special 40 (in the 2nd chart). That is why almost everyone here agree that Special 40 tends to produce punchier bass than S400 Mk ii.
I guess I was soooo customed to the boosted bass (all my existing speakers are) and felt unsatisfied with the more "neutral" bass response from Burchardt. I am getting (used) there. Burchardt gives me more days to consider keeping the speakers and I will try the best with all great suggestions offered here. Thank you all.
Buchardt S400 mk ii
Dynaudio Special 40