I have heard the criticism of kit wine as being too thin, without mouth, etc. and perhaps they are. I guess I have become inured to this because I prefer the fresh taste to that of commercial wines. To me, all I taste is chemicals in commercial wines and these are wines that I previously enjoyed. In talking to wine makers in Italy, I was told that they have to load up the wine that they export to the US with sulfites in order to protect it against the huge temperature swings that the wine could see in warehouses. Depending on to which state it is shipped and where in the warehouse it is stored, they had to protect against temperatures going from near freezing to above 110 degrees F.
There are some things that one can do to improve the mouth of kit wines, e.g. barrel age, add oak, add raisins, add grape skins, add tannin, add glycerin(?), etc. We don't know what commercial wineries add to the wine. I think a lot of people would be surprised to learn where the "head" comes from on some of the beers they drink.