I don' think that it was intended as a replacement for the ST1300. Rather, it is an expansion of the CTX series, as Honda indicated when they brought out the CTX700. While most of us prefer sport touring and adventure touring bikes, there is a market for that other segment. Our local dealer has done well with the CTX700, several for first time riders, women riders and those that don't feel comfortable with heavy or tall bikes. The cruiser market is a lot larger than the market for our favorite style bikes and I guess they are aiming at that, adding it to their F6B, Valkyrie, class, etc. I guess the CTX1300 may appeal to those riders that want that style bike, but want something a bit larger than the CTX700, but smaller than the 1800 offerings.
I rode the CTX1300 and if I had to tour on that, my trips would be very, very short. Not comfortable at all for me.
OTOH, our dealer has sold one ST1300 in the last several years, and he ordered that for a customer who wanted one, as he didn't stock them. They have neglected to upgrade that fine bike, but have continued to raise the price to unreasonable levels.
As one who has owned 1 ST1100 and 3 ST1300's, I see nothing in their line that interests me as a sport/adventure touring bike, which is why in 2011 I bought my first new Yamaha since 1973.