I find the age argument odd. Makeup and general cinema techniques can go a long way in this area. DY doesn't even look that old either it isn't too far of a stretch. There is also no reason to believe Wei has to be the same age in the movie. Finding a suitable person that can carry the weight of the combat is far more important.
Any ways. I always thought DY would make a good fit for this role. I'm instantly in for the martial arts.
Considering some of the environmental executions and brutality of the game I wonder how the movie will approach it. Hopefully they don't shy away from it.