Your description of the Meitner sounds a lot like Merason, I would be a little worried it would not be a significant change. I never thought I would say it, but I think I want a bit more edge, but certainly not bright.
I owned Meitner for over a year and have listened to Merason MK1 in a friend's system several times. I concur with your impressions. Both are polite to fault. After living with the Meitner MA3 for some time, I found that I was getting bored with the overly polite sound to the point that I stopped listening to digital altogether. Yes it was nice and smooth, but sometimes you want to hear that certain edge or energy (not to be confused with bright) when the fingers hit the keys on that piano or pluck the guitar strings. It was only after owning other DACs that I realized what I was missing.
Another point (not related to your post) I want to make is that the sound quality of a dac has very little to do with whether it's using a delta sigma, R2R, tube, or FPGA. After owning several dacs of every type, I firmly believe that it is the designer's skills, part quality and selection criteria, analog output section, and the fidelity of the clock that makes the biggest difference, regardless of whether it's ESS or R2R or tube or whatever. Just my two cents.