I was on the 4 day portion of the OP's cruise. It was my first time trying MSC. Realizing that a 4 day cruise is often not a good measure of what a line is really like, I am heartened to hear the OP's review. TBH, I was planning to post a largely negative review of the 4 day cruise, because in all honesty, it was not good in many respects [and to be blunt, some of the reasons for this were outside the control of MSC]. But now I won't do that, and I will give the benefit of the doubt to MSC until I take a longer cruise with them.
One thing I will note is about the buffet food, as the OP went into depth about it. Compared to other lines, there is simply substantially less variety if the 4 day cruise was indicative of what they would do on a longer cruise. That was true at lunch and at dinner, but particularly at dinner. Most other lines often have a "theme" night at the buffet each night of the cruise, and you end up with the normal staples, including Indian, asian, grill, and salad stations, in addition to five to seven additional dishes centered around the theme of the night. Not my experience on this 4 day cruise with MSC. Substituting salmon or veal or roast turkey at the rotisserie section was about as varied as it got.