I posted a similar response to
@joner7777 on the K1600 site as well, but the gist of my thoughts on the subject are below. I came off an ST 1300 as my previous touring bike and I liked it a lot. Now with a full year into my life with the K1600 GTL, I can honestly say that I have never owned such a satisfying machine. I absolutely could not imagine another touring bike. But there are still a handful of good choices out there for touring bikes, and none of them would be a bad decision.
Specifically with regard to the K1600...
Engine sounds as if it is over revving in every gear. The ST's V-4 and the in-line 6 cylinder engine of the K bike are very different beasts and the 6 is going to spin much more easily than the ST's v-4. It is just getting into its happy zone then.
Foot pegs are right where I would stand. My GTL doesn't seem to suffer from this issue, but there is a difference in positioning with the GT.
Fly by wire throttle is a nightmare and I keep stalling it as it has no feel as with old school cables. Can't really argue this point but only mention that it will take some time to get used to. I found that the K1600 requires more RPM's to get it moving than the ST did. I did my share of stalling it early on as well. One of my solutions was to install a set of Grip Puppies which aided with the finer control that I needed. It will get better to where you won't notice it.
Top box cannot be removed on overnight trips so attracting theft. This I don't understand and perhaps others can help out here, but the top box on my GTL is easily removable and I could bring it into a motel room at night if I wanted - I wouldn't, but I could if I wanted. Is the GT box different in that respect?
Feels top heavy when moving in garage. Absolutely no argument here. She is a heavy beast to grunt around the garage.
Then reading on the K1600 forum all the mechanical, expensive problems. I think you'll find the vast majority of K1600 owners (and any other BMW models) have no issues other than normal maintenance. With that said, a BMW will be more expensive once it gets into the shop than a Honda would. Nature of the beast.
Find what makes you happy. Life is too short.