Hi,
I have an X-T2, and yes it does get warm: at the bottom and elsewhere. If I turn the LCD screen down and touch the back of the camera, then it is hot there too. This happens with the new batteries too. This heat appears after a few minutes if one keeps the LCD and the camera on. To reduce the heat, I switch the LCD off and use the eye sensor to turn the EVF on when I look through it. This works well, but i have not tried it in hot weather.
The camrea is warm but not extremely hot.
The heat happens when I take still photos. I do not take videos. WIth 4k I guess it will produce more heat.
I tried another X-T2 and it got warm too. One amazon review also mentions the heat problem. I also read it somewhere in a review from a professional person.
When the ambient temperature rises, one will probably have more heat, since the camera cannot dissipate its heat as easily.