It is a good bike for gravel. I know, as I have about 3,500 miles on my Giant TCX. Have really enjoyed it on the gravel. With that said, though, I know exactly where the lower BB drop crowd is coming from, as I have recently purchased a Salsa Journeyman. I have noticed several differences in how the two bikes, "feel", when compared. Also, I am 51 years old. I believe my age does make a difference, as well.
The TCX is a bit more difficult, for me at least, to control, and handle in the deeper gravel, as well as the rough sections. When on the TCX, it seems to me that I have to be "all over it". It takes more energy, thus am more tired, at the end of a long ride on the TCX, versus the Journeyman. Am limited, on my TCX, to running 35mm width tires. Currently, am running 32mm MSO's. The TCX is more responsive. It is a bit harder on the back, as I am leaning forward more on it.
When I ride the Journeyman, with the lower bottom bracket, I don't have to be all over the controls to stay vertical. It is definitely a much more relaxed type ride experience. Don't get me wrong, it has it's moments in the deep, and sketchy stuff, too. Overall, though, it takes less energy for me to ride this one on gravel. Also, at the end of the ride, the more upright, and stable feeling, is easier on me. Seems like I don't have to put out as much effort, to stay in control. Between the two, the Journeyman is definitely an easier ride, and more comfortable experience on the gravel.
Keep in mind that all of this is very subjective. What I have experienced may be totally different from what you experience. Enjoy that TCX. It is a great bike for gravel. I have posted reviews of both my TCX, it is a carbon version, as well as the aluminum Journeyman on this site. By the way, I still love my TCX. I have no plans on parting with it. It is one of my favorites.
The main thing, in my opinion, is ride. Being on the gravel is how you get experience. The more you ride, the more you will find what works, and what doesn't work for you. Reviews are great, but you will form your own opinions, out on the gravel.