Hola. What your ears are telling you? You must trust them. We can not listen it, only your findings and your comments. I do not see any fault in your system. Also depends of what are you listening and at what SLP are you playing your music and videos. For sure, I would like to have everything electrostatic. But right now, in my system, I am using for rear a pair of Motion 4, and I do like them better than my prior Electa model from Sonus Faber. I wish that I could use an electrostatic speaker, but the truth is: my room is too little.
The Vistas are very good sounding speaker and they have tons of resolution, coherence and dynamics. The harmonic texture of the piano is resolved easily and effortless. Guirtars, wind instruments, percusion, you name it, sound very nice and well balanced. I have a Motif as center too and it is the second best of ML center channel line. The voices are natural and very easy to understand. Easy to drive and also has the electrostatic transparency as your Vistas. I recommend to you the Grotto I sub or the Depth I. Everything it is a matter of liking. Me, as an example, I do like tubes. My main power amp is an Audio Research VT-100 MKII, modified. So, if you like tubes, you could get a tube power amp. But again, it depends of what kind of sound are you looking for. Hope this might help a little bit, happy listening,
R.