Actually I remember there being real discussion about a direct china flight, maybe x2 weekly, could the 787 open this up again as a possibility? China Southern NCL-CAN? Maybe shared with x5 weekly MAN-CAN?
TK and EK would not effect each other much, honestly... Many more TK passengers would be O&D than DXB passengers (although they are on the increase, think it's about 60% now). TK fly to many other countries, and secondary cities within those countries. They would also cater for Eastern Europe too. Apart from a small percentage who will connect to East Asia and some African destinations who will have the choice of EK or TK which wil likely depend on price/loyalty/journey time etc. Some may prefer the equal split in journey time offered via DXB rather than a short flight-long flight offered by IST/AMS/LHR/CDG. Then there's also the small matter of a 151 seat 737 900ER vs a 427 seat 777 300ER