It seems, my general mistake was: I quite turned up the master volume to give the tubes the chance to "get going". And since this amp is REALLY loud, I had to turn down the channel volumes. By doing so I cut the sound. After adjusting (channel up and master down) it sounds better. More open.
But what so ever, I fully agree, one has to set up own sounds. Although the presets can serve as a first idea. I do not play in a cover band, so I am fine with a "handfull" of different tones. Moreover, I use the MKii 212 as a second amp besides a "classical tube amp". I found the MKii does an excellent job as "enhancement amp". I also use him sometimes as "single amp".
I recenty read they gave up producing the Valve. Maybe it has too many choices for "classic amp" players. And, as I found, one really needs to tweak the sounds quite carefully till they fully match to what one is looking for. Needs some knowledge (e.g. about effects), time, and patience.