Hmmmmmm! There are pro's and cons. However, if you follow the TA's current logic to link cars into 4 & 5 car links, I suppose your idea is the next logical step. That's not to say that I agree. Right now I can unlink and mix cars from other links in an hour or two. Articulated cars are far more difficult to do this with.
Another thought. If you want to articulate 60' cars, you'd possibly run into clearance problems. Currently, truck centers on an average 60' car is 44'7" If you articulate them the end cars would have truck centers of more than 52' and the center car(s) would be over 60'. Clearly, these cars would sweep wider on the curves and might scrape bench walls. (Truck centers on 75' cars are only 54'.
WARNING !! NUMBERS ARE APPROXIMATE ONLY AND ARE MEANT TO BE ACCURATE WITHIN A FEW INCHES ONLY. I APOPOGIZE FOR ANY DISTRESS THIS MAY CAUSE CERTAIN SUBTALKERS.